DOCUMENT RESUME

ED 057 625 EM 009 486

TITLE Computer Communications, Cooperation or Confusion; ACommunications Conference at San Jose Statecollege.

INSTITUTION San Jose State Coll., Calif.PUB DATE Jan 72NOTE 51p.; Proceedings of the Annual Computer

Communications Conference (First, San Jose,California, January 24-26, 1972)

EDRS PRICE MF-$0.65 HC-$3.29DESCRIPTORS Cable Television; Communication Satellites;

*Computers; *Computer Science; Conference Reports;Confidentiality; Information Networks; *Networks;*Technological Advancement; *Telecommunication;Telephone Communications Industry

IDENTIFIERS Wired Nation

ABSTRACTThe papers from a conference on computer

communication networks are divided into five groups--trends,applications, problems and impairments, solutions and tools, impacton society and education. The impact of such developing technologiesas cable television, the "wired nation," the telephone industry, andanalog data storage is projected. Various applications ofcommunications networks are described; among them are a nationalbiomedical network, an air traffic control system, and amodernization of the U.S. Postal Service. Some of the problems causedby costs, time-sharing, voice grade communications and othertechnical considerations are examined. The solutions to somedifficult technical problems are offered. The effect on society ofincreased communication between computers is discussed withparticular emphasis on the rights of the individual to privacy andconfidential information. (JY)

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PROCEEDINGS OF THE

ALCOMPUT CATIONS

AT SA STA E COLLEGEJAN 1972

U.S. DEPARTMENT OF HEALTH.EDUCATION & WELFAREDFFICE OF EDUCATION

THIS DOCUMENT HAS BEEN REPRO-DUCED EXACTLY AS RECEIVED FROMTHE PERSON OR ORGANIZATION ORIG-INATING IT. PGINTS OF VIEW OR OPIN-IONS STATED DO NOT NECESSARILYREPRESENT OFFICIAL OFFICE OF EDU-CATION POSITION OR POLICY.

COMPUTER COMMUNICATIONS, COOPERATION CIR CONFUSION

A CONIPUTER COMMUNICATIONS CONFERENCE AT SAN JOSE STATE COLLEGE

1

In cooperation with:San Francisco Peninsula Chapter ACM, San Francisco Communications Technology Group IEEE,NASA/Ames Research Center, Philco-Ford, Pacific Telephone and San Jose State College

PROCEEDINGS OF THE

FlCOMPUT

AT SAJA N

ALCATIONS

TE COLLEGE1972

EXECUTIVE COMMITTEE:Naim Abou-Taleb, Ph. D., Chairman,

Professor of Electrical Engineering,San Jose State College

(408) 294-6414 X2682Lawrence D. Prehn

Customer Services Engineer,Pacific Telephone & Telegraph

(408) 291-4065Robert N. Linebarger, Ph. D.,

Computer Systems Scientist,NASA/Ames Research Center

(415) 961-1111 X2968Dennis R. Allison

Representative, San FranciscoPeninsula Chapter ACM,Physicist, Radio Physics Laboratory,Stanford Research Institute

(415) 326-6200 X3926Edward F. Carr

Representative, CommunicationsTechnology Group IEEE,Staff Engineer,Pacific Telephone & Telegraph

(415) 399-5550

EXHIBITS:Robert C. Roe

Paradyne Corporation(408) 246-6280

PUBLICITY:Bradford P. Gibbs

NASA/Ames Research Center(415) 961-1111 X2001

PUBLIC RELATIONS:Jan C. Matser

I nformatics Inc.(415) 961-9130

FAC I L IT1 ES:Roy C. Berner

Pacific Telephone(408) 291-4032

CONFERENCE COORDINATION:Art Wagner

San Jose State College(408) 294-6414 X2206

CONFERENCE SECRETARY:Evan Moustakas

San Jose State College(408) 294-6414 X2206

In cooperation with:San Francisco Peninsula Chapter ACM, San Francisco Communicaticpns Technology Group IEEE,

NASA/Ames Research Center, Philco-Ford, Pacific Telephone and San Jose State College

2

TABLE OF CONTENTS

SESSION 1 - TRENDS

Chairman: A. J. Lipinski, Institure for the Future

"IMPACT OF INFORMATION TECHNOLOGY ON THE FUTURE DIRECTION OF U.S. SOCIETY"

W. W. Harman, Stanford Research Institute

"IMPACT OF CATV ON THE COMMUNICATIONS INDUSTRY AND THE PUBLIC"

E. M. Allen, Western Communications, Inc.

"COMPUTER COMMUNICATIONS IN THE WIRED NATION OF THE FUTURE"

D. A. Dunn and E. B. Parker, Stanford University

PAGE

1.1

1.2

1.6

"THE FUTURE OF THE TELEPHONE INDUSTRY" 1.8

A. J. Lipinski, Institute for the Future

"A REQUIEM FOR ANALOG DATA STORAGE" 1.8

M. O. Felix, Ampex Videofile

SESSION 2 APPLICATIONS

Chairman: E. M. Van Vleck, NASA-Ames Research Center

"PATHS TO AN INFORMATION UTILITY"

E. M. Van Vleck, NASA-Ames Research Center

"A NATIONAL BIOMEDICAL NETWORK"

J. E. Burtt, Lockheed Missiles & Space Company

"FAA'S 'IDIOM AIR TRAFFIC CONTROL SYSTEM"

J. O. Thomas, Federal Aviation Administration

"EXPERIMENTS WITH SATELLITE DISTRIBUTION OF COMPUTER ASSISTED INSTRUCTION"

J. Ball and D. Jamison, Stanford University

"INSTANT RETRIEVAL TELEVISION: FROM THEORY TO SYSTEM"

L. H. Day, Bell Canada

"EVALUATING COMPUTER APPLICATIONS

R. M. Hough, Stanford Research Institute

2.2

2.4

2.6

2.8

2.10

"COMPUTER COMMUNICATIONS APPLICATIONS IN THE U.S. POSTAL SERVICE" 2.12

J. V. J. Ravenis II, General Dynamics Corporation

"COMPUTER TO COMPUTER COMMUNICATIONS VIA SATELLITE DATA LINK" 2.15

H. A. Bustamante, Philco Ford WDL

SESSION 3 - PROBLEMS AND IMPAIRMENTS PAGE

Chairman: D. P. White, The Service Bureau Corporation

"TRANSMISSION CONSIDERATIONS BETWEEN SWITCHED SERVICE AND PRIVATE LINE 3.1DATA COMMUNICATIONS"

R. D. Hailey and F. E. Ward, Pacific Telephone

"COST EFFECTIVENESS EVALUATION OF CONCENTRATORS IN DATA COMMUNICATION NETWORKS"

N. F. Schneidewind, Naval Postgraduate School

"DROPOUTS AND PHASE-HIT EFFECTS ON DATA CHANNELS"

L. A. Sibley, Pacific Telephone

"THE RJE ENVIRONMENT: HIGH-SPEED VOICE GRADE COMMUNICATIONS"

R. Larribeau, Jr., Information Systems Design, Inc.

"COMMUNICATIONS IN A TIME-SHARING NETWORK"

D, E. Carriger, The Service Bureau Corporation

SESSION 4 - SOLUTIONS AND TOOLS

Chairman: E. J. McCluskey, President. IEEE Computer Society

"SIMULATION IN COMPUTER COMMUNICATIONS"

N. A. Taleb, San Jose State College

"INTERACTIVE MANAGEMENT OF MINERAL RESOURCES - PRACTICAL EXPERIENCE WITHTHE ALASKA DATA-BASE"

J. F. Valee and C. Askevold, Stanford University

"CODING REQUIREMENTS OF DIGITAL REMOTELY CONTROLLED SYSTEMS"

S. M. Yousif, Sacramento State College

"CHANGING COMMUNICATIONS TECHNOLOGY AND THE TELEPROCESSING BOOW

D. G. Schutt, Pacific Telephone

"THE BACKGROUND, ECONOMICS AND APPLICATION OF THE CASSETTE TERMINAL"

S. C. Bachua, University of California at Santa Cruz

"COMPUTATION AND-COMMUNICATION TRADE-OFFS IN MILITARY COMMAND AND CONTROL SYSTEMS"

N. E. Willmorth, System Development Corporation

"SYNERGETIC MEASUREMENT TECHNIQUES FOR DATA TRANSMISSION"

R. M. Tweedie, Pacific Telephone

SESSION 5 1 IMPACT ON SOCIETY AND EDUCATION

Chairman: G. D. Wallenstein, Consultant

"HUMANITY IN MEGABITS AND MICROWAVES"

G. D. Wallenstein, Consultant

"SOCIETY: KEY ELEMENTS FOR THE FUTURE"

A. Mitchell, Stanford Research Institute

3.4

3.6

3.7

3.8

4.1

4.2

4.3

4.4

4.5

4.6

4.7

5.1

5.2

"THE SOCIETAL SIDE OF THE WIRED CITY"

D. Atkinson, Bell Canada

"ECONOMICS OF PRIVACY"

K. R. Walters, Pacific Telephone

PAGE

5.4

5.6

"THE IMPACT OF CYBERNETIC AND COMMUNICATION TECHNOLOGIES ON EDUCATION" 5.7

R. B. Johnson, Education Engineering Associates

"MACHINES AND TEACHERS" 5.7

R. Parkman, San Jose State College

IMPACT OF INFORMATION TECHNOLOGY ON THE FUTURE DIRECTION OF U.S. SOCIETY

Willis W. HarmanDirector, Educational Policy Research Center

Stanford Research InstituteMenlo Park, California

94025(415) 326-6200 Ext. 4451

Forecasts of future-shaping applications of information technology are by now commonplace--inbanking and finance, industrial process control, engineering design, research and education,medicine, new types of communication services, individual home applications, and many other areas.

Negative impacts of information technology typically mentioned include invasions of privacy,Big Brother surveillance by governments, movement toward a centralist cybernated economy, politicalleadership problems brought about by the possibility of "instant plebiscite."

Advances in the storage, retrieval, processing and distribution of knowledge have become anindispensable part of the technostructure of modern society. The business life of the nation ctould notgo on without them. The new ways of handling information have brought about fundamental changes ingovernmental and political processes. They have altered the psychological and cultural attitudesof hundreds of millions who have only the haziest notions of how the new technology works.

The cultural impact has already begun to show itself. There is a schism between those of the elitegroup who know how to exploit the systematized knowledge in which the new information technologytraffics--and the majority who-fear manipulation by that knowledge power which they only dimly under-stand. This split is manifested in a growing anti-expertise sentiment.

The fears have some foundation. It is easy to imagine ways in which these technologies might beused to facilitate the centralization of power; the cynical manipulation of political, economic andcultural publics; the regimentation of thought and work; the devalw-tion of every part of life thatcannot readily be quantified or otherwise processed.

Information technology can be a potent tool applied to the governing of societal processes and theresolution of societal problems--poSsibly thereby contributing to an ever more powerful centralizedgovernment. It can also constitute a means by which decentralized democratic government can befacilitated. The balance between these two may be one of the most fateful choices the society willmake in the last third of this century.

This issue is but one facet of a more fundamentgl problem the society faces--namely that themultitudinous individual microdecisions which comprise the everyday activity of the technostructure(e.g., to employ knowledge, to apply a new technology, to create and take jobs, to use scarceresources, to affect the environment) are currently adding up to largely unsatisfactory macrodecisions.There are a-number of reasons this is true to an extent it was not true in the past. A tendency, for

the past four decades at least, has been for increasing reliance on government to provide the regulationto keep the macrodecisions in a tolerable range. But this leads in the direction of bureaucratic

giantism and centralized control. There is another way to go; however it requires a shift in theoperative values of persons and institutions.

1.1

Impact of cATV on the Communications Industry and thePublic E. M. Allen, Western Communications, Inc.

As a representative of the CATV industry, it isindeed a pleasure for me, both as a Bay Area cabletelevision operator and as a Director of the NationalCable Television Association, to be offered this oppor-tunity to address your Conference.

Frankly, as only about 87 of the people of theUnited States even know what the CATV industry is (andthat CATV stands for "community antenna television"),our industry needs and welcomes the greatest possiblepublic exposure we can get. In this regard, somepeople refer to us as Cat-V and, on occasion, Cat-Five.To clarify at the outset, our industry is not Cat-V orCat-Five or, for that matter, Pay Television - it isCATV it is "community antenna television" - it is"cable television". However, as I shall try to pointout in my remarks, we now have the exciting opportun-ity and in the rather near term, to become somethingsubstantially more than just our present "good recep-tion" service.

As the Bay Area has such a high degree of CATVsubscribership, I am going to assume that all of youknow what is meant by CATV. Therefore, I'll avoid thekindergarten definitions as to just what CATV is (orisn't) and go directly to my remarks.

I should like to address my remarks to the ques-tion "What will be the impact of cable television onthe future of our present communications industry".It wasn't too many years after cable television cameinto being (about 20 years ago) - after broadcastersgot over the shock of having someone expand their areaof coverage for free - that Monday morning quarterbacks,prophets, and other assorted seers began making predic-tions about CATV's impact on radio, television, news-papers, magazines, the Telephone Company and just aboutevery other form of communications that exists in thiscountry. Some saw the early demise of television -just as earlier Cassandras saw the demise of radio assoon as those fuzzy, jerky images first appeared onthat unwieldy box in our living rooms. In fact, as anowner of a radio station, I must admit to being one ofthose early Cassandras and even went so far as to sendmy business cards back to my local printer to have them

over-printed in red with the message "Help stamp outTV". And, of course, it -was predicted that newspapers,as we presently know them, would ultimately be doomed

just as soon as cable got around to transmitting outdaily news by facsimile.

Now, some ten years after this initial wailingbegan, the prophets of doom are still at it. Cabletelevision has grown quite a bit - there are now over2,700 systems serving some six million homes in about4,500 small communities across the nation - and cabletelevision's impact is now an even hotter topic. Myreference to these early prognosticators may give youan idea of what we are up against in trying to predict

the future impact of cable television. With just afew exceptions, we don't have much actual experienceto go on. To steal a line Alvin Toffler used in hisbook, Future Shock, "To prophesy is extremely difficult,especially with respect to the tuture".

Keeping that in mind, let me offer this proposi-tion: The impact of cable television on our existingcommunications system will be quite minimal. On theother hand, the impact of cable on the public at largewill be nothing less than revolutionary. Can these

two statements square? I hope to marshall the evidenceto show that they can.

First, I Would ask you to consider this rathermundane truth. Times change, and we are forced tochange with them. When you consider cable television's

impact on broadcasting, for example, you should remem-ber that broadcasting, in five or ten years time, willnot be what it is today. The same is true of newspapersand, probably, of radio. Look closely at each of thesemedia and try to recall what they were like twenty yemsago. I think you will find that there are substantialdifferences between what you saw and read and heard in1950 (and how it was presented) as opposed to what yousee and read and hear now (and how it is presented).Perhaps some will argue there is not enough difference.But differences there are - and there will be many moreby 1980. The pace has quickened - the needs havechanged.

Admittedly, cable communications will be one ofthe elements that stimulates change in these businesses,or at least I hope it will. But it is by no means thesole element. There are other potent forces at work -social, politital, and governmental pressures, previous-ly unarticulated public needs, new technologies andtechniques. Business has adapted in the past, and itwill continue to adapt. Competition is still a goodidea and still the best way I know of to get a betterproduct. In short, there should be little questionthat the media of the future will be quite differentfrom what they are now.

Parenthetically, I sometimes think this is one ofthe great problems that exists between broadcasters andcablemen. A television broadcaster looks at his busi-ness now and, for the life of him, can't imagine how hecan continue that business with competition fromNicholas Johnson of the FCC, the D.C. Court of Appeals,irate mothers, minority groups on both the left andright, newspapers, radio and cable television to boot.The catch is, even if cable didn't exist, he wouldprobably be doing something quite different in thefuture anyway because of these and other pressures.

In considering cable's impact on existing media,let's first look at the TV networks, independent UHFand VHF television stations .nd newspapers.

In seems clear that there will be minimal, if any,adverse economic impact on the networks or their affil-iates. Their general share of the audience in Americaseems impervious to assaults of diversity. It will bea good long time before any cable outfit, network orotherwise, is in a position to compete with the networksfor programming.

Perhaps the best indication of cable's competitivethreat to the networks comes from network executivesthemselves. In the past year I have seen statements(in Business Week and U.S. News & World Report) fromNBC's Julian Goodman, ABC's Jim Duffy, and CBS' DavidBlank all dismissing the threat of cable. In fact, Mr.Blank says, somewhat deprecatingly, "In the decade ofthe 70's, I'm doubtful that more than 25 percent of thecountry will be hooked up to cable". Well, right nowless than ten percent of the country is hooked up. Thatextra 15 percent doesn't seem to bother him in the lea9t.At least publicly, the networks don't seem to fearcable's impact.

What about independent stations, both UHF and VHF?Here is where the so-called "controversy" lies. We'veseen detailed economic studies and statistical compilations attempting to gauge the impact of cable on theseTV stations. Frankly, the issue has just about beenbeaten to death. What can we glean from all the debate?First, there is no documentation of any TV stationgoing under, or even suffering substantially, becauseof competition from a cable system. That is based uponempirical evidence. In fact, a few years ago a friendof mine in the cable television industry offered areward of $10,000 to any television station which coulddemonstrate'that it had been substantially adverselyaffected by cable television competition and, to date,

1.2 . .

that reward is still uncollected.

But from there we slop into the realm of prophesy.The hard-line adamant broadcaster expresses concernabout what happens when distant television signals arebrought into "his" market. He claims those distantsignals will destroy him.

Yet, every major independent and impartial studyin recent years (and I emphasize "independent" and"impartial") has recommended fewer restrictions oncable. The Rand Corporation reports, the new Sloanreport, the report of President Johnson's Task Forceon Communications Policy, the Office of Telecommunica-tions Policy, the Justice Department's memoranda on'cable policy, even the Federal Communications Commis-sion's own detailed and exhaustive staff studies argueagainst the demise of so-called "free TV" if thepresent restrictions on cable are loosened.

In fact, many of these studies claim that indepen-dent stations in both large and small markets, especial-ly UHF stations, may well be helped by the advent ofextensive cable penetration. That is certainly thecase here in the Bay Area- just ask Channel 44 in SanFrancisco, or Channel 40 in Sacramento, or 36 in SanJose. In the.case of UHF stations, the extendedcoverage provided by cable, equalized (and better)signal quality, and the ease of tuning which CATVgrmswould seem to more than offset any audience diminutioncaused by multiple signal availability. And, in yetanother way, predicted audience fragmentation willalso be lessened by the fact that these same studiesshow that CATV subscribers tend to watch more tele-vision, rather than viewing the local signals less.

Even if at some point in the future, it could beadequately demonstrated that cable competition issignificantly harming a television station to thedetrIonent of the public interest, steps could be takento meet that problem on an ad hoc basis, through whatis called a "failing station dOctrine". What shouldnot happen, however, is that public policy be predica-ted on questionable and .ndemonstrated presumptions ofsome imagined threat. In such a case, only the publicis the loser.

What of newspapers? Again I would turn to aspokesman for that industry. Stanford Smith, Presidermof the American Newspaper Publishers Association, incomments recently submitted to President Nixon'sCabinet Committee on Cable Television said, "We viewthe cable medium as a positive adjunct or complementaryavenue for the dissemination of information - specifi-cally news". Interestingly enough, ANPA also attachedto its comments an article titled "Local Programs onCATV - No Major Menace to Newspapers".

I think it is safe to say that the newspaperindustry sees no tremendous threat from expanded cabletelevision service. Certainly, for the near term,printed media have a time advantage over all audio/visual media in that people can and will read a news-paper or magazine when they want to. Additionally,cable's competition for the local advertising dollarwith the newspapers has been likened to the competitionthat exists today between a newspaper and an indepen-dent UHF station -- certainly not an unhealthy situa-tion.

Perhaps, many more years down the pike, cable mayrepresent more of.a threat to newspapers, but I wouldsuspect the threat will come not from cable per se,but from such problems as newsprint and productioncosts, and union troubies.

In the meantime. I, as does Mr. Smith, see cableas a positive adjunct to newspapers. Already we areseeing many situations where local small town news-papers are developing cooperative arrangements with

1.3

CATV systems.

Finally, a word about the telephone company. Asyou may know, telephone companies have been barred fromproviding CATV service in the same area where theyprovide the telephone service. This and other FCCrulings have made telephone company involvement in thecable industry difficult. However, that is a matter ofFederal regulatory policy, not cable competition per se.

On the other hand, as cable grows and begins toacquire the means for providing extra services suchas utility meter reading - an interesting competitivesituation could begin to develop between cable and theutilities. It's difficult to say much about what willdevelop here in terms lf Federal policy - but it'shardly thinkable that cable will put the telephonecompany out of business. They've already wired up thenation; we're just geCting started.

The second half of my proposition is that CATV'simpact on the public at large will be nothing less thanrevolutionary (and this will involve you). You mayfairly ask that if cable's impact on everything elsewill be minimal; how can it have a revolutionary impacton the public? Several things explain this. First,and most obviously, all of cable's benefits are notgoing to come showering down on the public in the nexttwo years. In particular, some of the more esotericservices facsimile reproduction, information retrievalthrough computers, home shopping, burglar and firealarmservice - although technologically possible now (tosome degree), are some years away on any large scale.However, you should know that in many c these areaspilot programs are already in the works or operating.

Secondly, and most important, don't presume thatcable will be doing only those things that other mediaare now doing. If that were true, then cable wuuldhave to supplant other media in order to be viable.

If you look closely, you find that cable will besupplementing not supplanting existing media services,offering new services, meeting needs that are not nowbeing met due to economic and technical limitations.This is why cable's impact on the public will be revo-,lutionary.

These services touch upon almost every aspect ofmodern man's existence. In addition to their intrinsicvalue, they hold the promise of spreading the benefitsof technology to low-income and disadvantaged groupsby making education and information more readily avail-able. In fact, it is the less-favored groups of societywho can be the real beneficiaries of the development ofCATV, both absolutely and relatively.

Let MR be specific about some of the possibilitiesthat seem most hmmediately realizable. Can open circuit(or over-the-air) television serve as a means for alummmunlimited local expression, for community or even neigh-borhood expression? I submit it cannot. It tries to,and in some cases it does a good job, but it is limitedby its single channel and, because its financial baseis commercial advertising, the need to reach a massaudience. I don't think you will find too many broad-casters who can or would argue that point. Cable can,through leased and public access channels, and trulylocal origination facilities, offer this unique oppor-tunity because its financial base is its subscribers.

What about the educational possibilities? Againbroadcast television is limited. In addition to theobvious single channel limitation, educationallyspeaking it is.inflexible, passive, and certainly tooexpensive. It is not insignificant that what was oncecalled "educational television" is now generally called"public television". Despite years of involvement,untold experiments, many false starts, and millions ofdollars, television and education have not had the

happiest of marriages in this country.

Several weeks ago, a Rand Corporation study con-cluded that cable television can serve instructionalneeds in education in a far more flexible and expandedmanner than can over-the-air broadcasting.

There are very real opportunities for capitalizingon the educational potential of the audio/visual mediumthrough cable television, provided educators and cablepeople can get together in a realistic, cooperativemanner (and that hasn't always been the case). Thiswill be especially true when two-way interactive cablebecomes a reality.

So far, I have touched only on the new cable ser-vices which seem to be most immediately possible. I

have deliberately avoided a discussion of the "blue sky"aspects of our future. In fact, I have been critical ofour industry for the emphasis some members of the indus-try seem to put on these exotic "blue sky" services.Frankly, in the heat of competitive franchise battles,some members of our industry have promised the localgovernments services that, at the moment, we just can'tdeliver. Some of the publically-held CATV companiesseem to have a penchant for extolling the "blue sky" inour future - perhpas as a way of supporting the priceof their stock. I think, for the moment, we should soft-peddle this "blue sky" talk we are only doing ourindustry a disservice.

However, at a Conference like this, we must admitthat the "blue sky" does exist and in the foreseeablefuture the computer industry and the CATV industry aregoing to be working partners in turning the "blue sky"into reality.

I mentioned the fact that there are some 2,700cable systems presently operating in this country. Ourindustry has a present image of itself as a one-waydistribution system and these 2,700 systems, whilecapable of delivering information into the home, do nothave the ability to extract information from the home.Thus, our future depends totally on the two-way capabil-ity of systems yet to be built. The consumer has apresent desire (and it has been building for yeavs) toend his passive viewing role and actually communicatehis wishes for goods and services without leaving thecomfort of his home. AA the, Chairman of the FederalCommunications Commission, Dean Burch, told our Nation-al Convention in Washington last July, "What ultimatelytips the scale in favor of cable's orderly growth arethe benefits cable can bring over and beyond the meredistribution of commercial broadcast signals. Thesesupplemental benefits are...the key to cable's future.Not sometime in the next century, or the next decade,but starting now". Among the services cited for this"remote control living" are:

-Doctors making electronic house calls via cable.- ppilmles providing employees at-the-desk

-IvErmligolice and fire department contact with

- Instant polling of the populace on vital issues.Consumer retrieval of facts from computerizedlibraries.

-Shopping from the home.-Transmission of business information from officeto office by special circuits hooked up to tele-vision sets.

Yes, the true future of our industry lies in thetwo-way systems yet to be built. These systems will bebuilt - the Government :rill insist they be built - the

consumer will insist they'be built- In fact, prognas-ticators in our industry envision that ten years fromnow only one-fourth of our income will come from the .service we are presently providing (the distribution ofmore and better television pictures) and three-fourthsof our income ten years from now will be from services

l-o

we are not now providing (or, in some cases, not evendreaming of).

A certain limited number of two-way experimentsare'presently under way. One of my own systems (inSouth San Francisco) has an operating two-way linefrom its studio to the headend. Experiments are underway in Los Gatos and El Segundo, California, in Reston,Virginia, in New York City, in Orlando, Florida, andin Overland Park, Kansas.

Just how fast this two-way concept will develop is,realistically, a matter of economics. While we have alimited capability now, much more R&D must be done onsome of the necessary hardware to fight the costs downto where they are realistic. For example, it is esti-mated that, at the present, the simplest two-way ter-minal would presently cost between $200 and $400. If

you add a feature which would permit the customer toinsert his credit card into the terminal, the costcould go to $500. A feature which would enable thegas or water company to read the meter without sendinga man into the house, could increase the costs of theterminal device to as much as $600. If you add a videotaperecorder-player (which could enable the customer toautomatically record a TV program, store it in his TVset, and play it back through the set at a later time),the cost could go to $800 and if we are talking abouta complete two-way video communication system, theterminal costs could soar over $1,000.

Another part of the economics, in addition to thecost of the hardware, is the customer's willingness topay for these extra services. Stanford Research Insti-tute, in their studies, feel that people will pay about$5 a month above their basic cable charge for eachadditional service that interests them - to a limit ofabout $20 per month for the entire package. Unfortun-ately, SRI also estimates that the present costs forsuch a package would be about $40 per month - or sub-stantially out of the financial reach of our subscribers.

How far away, realistically, are these new ser,does?The Rand Corporation feels that some of the simplestservices are still at least five years away and thatit may be a decade or more before many home subscri-bers ea', make requests over their cable for special-ized information or services from many differentsources. So, at best, we're not talking about the"near" near term. The new systems have to be built,the R&D has to be done, and the demand has to begenerated.

So, in summary, my point is just this. Cabletelevision will not destroy or supplant existing media.Those media will continue to exist; changing, adapting,doing what they best can do. Some of that change maybe due to cable, but much of it will come from otherpressure - pressures which business has always facedand will continue to face.

Conversely, cable will do that which it best cando - essentially what no one else has been able to door has wanted to do.

I have said a good deal about impact today. Inclosing, let me plug in one more type of impact. Thatis the impact of government regulation on cable (atthe local, State and Federal level) and of the contin-uing attemps to have cable's growth thwarted. For thepast three years the CATV industry has been laboringunder what amounts to an absolute freeze on its growthin the top 100 markets of this country - the marketswhich contain about 857 of our population. Last sum-mer, the Federal Communications Commission, afteryearsof deliberation and study, arrived at a compromiseplan for cable's controlled and orderly growth whichwas presented to the Congress in a Letter of Intent onAugust 5th. Unfortunately, hard-line opponents of

cable's gruwth were not disposed to accept that compro-mise. Through heavy pressure at the very highest levelsof government, they have now succeeded in rammingthrough still another and still more compromisingposition. It was with substantial reluctance that Iparticipated in our industry's national deliberationsin which we ultimately (and most reluctantly) acceptedthis additional compromised position.

Now the new law has been written. Whether, or if,our industry is to be permitted to move ahead and servethe remaining 90-plus percent of the population of thiscountry, will depend on how the language of this newReport and Order is translated into actual FCC regula-tion. The same forces who are motivated by politicalexpediency and narrow self-interest are still workinghard to dilute the ultimate capability of cable tele-vision. If they succeed, many of the services I haveoutlined to you today will be delayed, opportunitiesfor important services needed now will be lost, and thepublic will be the big loser. That would be the veryworst type of impact associated with cable television.

However, if I may shift from my former position asa Cassandra to that of a Pollyanna, I sincerely feelthat, with this newest compromise position now a matterof public record and concurred in (albeit reluctantly)by the broadcast industry and the cable televisionindustry, "reasonable men reasoning together can arriveat reasonable solutions". It is said that the hall-mark of a true compromise is tilat nobody is fullysatisfied with the result. I can assure you thatneither the broadcast industry nor the cable televisionindustry is fully satisfied with these newest regula-tions. And so, while the near term for cable televi-tion is not as near as I should like to see it, I thinkwe are now ready to take that first step down the longroad which will le.d u ultimately, to a communicationsrevolution of unparalleled benefit to the Americanpeople and in a manner that some of our "blue skyprojectionists" have not yet even dreamed.

Cable Qelevision, as I see it, will be the mostexciting an0 Ilotentially explosive industry on thehorizon in the next decade. It will be absolutely ona par with our space efforts of the last decade butwill truly reach and touch the lives of so many moreaverage American citizens. It goes without saying,that I am both proud and privileged to consider myselfa part of this revolutionary new concept of serviceto all mankind.

1.5

10

Computer Communications in the Wired Natio.1 ofthe

D. A. DunnAssociate ProfessorEngineering-Econamic

Systems Dept.Stanford UniversityStanford, Calif. 94305321-2300 X 2330

FuturebyE. B. ParkerProfessorCommunication

Dept.Stanford UniversityStanford, Calif. 94305321-2300 x 2755

Broadcast television is like the passenger rail-road, taking people to scheduled places at scheduledtimes. Cable television has the potential to be likea highway network permitting people to use their tele-vision sets like personal automobiles, selecting in-formation, education and entertainment at times andplaces of their own choosing. The technology of cabletelevision (especially two-way cable television),video cassettes, computer information systems and com-munications satellite can permit the creation of an'information utility' which could be used to fosterequal social opportunity for every resident of theUnited States.

Present cable television systems. At presentthere are 57 million television households, of which4.5 million are served by cable (1). The typicalcable television system now has 12 or fewer channelsof television capacity, primar:ily used for retransmis-sion of broadcast television. Revenue is obtained byselling (at rates of about $5 per month) better qual-ity television signals than those available over theair, or by selling reception of distant signals notlocally available.

A single television cable has the capacity formany more than 12 television signals, since presentday cable amplifiers can amplify frequencies fromzero to about 300 Megahertz (MHz) and a bandwidth of6 MHz is required for each color television signal.

In order to estimate the cost of the hardware fora 24-channel System (and more camplex systems dlsolssedbelow) the capital cost of a complete cable system isfirst calCulated. The capital cost is then convertedto a monthly cost and then to a cost per terminal hourthat a user would expect to pay and a cost per Channelhour that would have to be paid by any group or indi-vidual making exclusive use of a channel.

The capital cost of a cable system per user de-pends strongly on the density of homes. For a densitytypical of urban locations with medium density, 50,000homes or apartments can be served by 100 miles of dis-tribution plant. Taking $15,000 per mile as the costof the underground trunk line cables, allowing $45 persubscriber for house drops, and $50,000 for head-endbuildings, antennas and related costs, a 10,000 sub-scriber system with 50% market penetration would cost$110 per subscriber. These cost estimates are fortypical underground systems and are based on informa-tion provided by the National Cable Television Associa-tion as reported by Comanor and Mitchell (2). To con-vert capital cost.to monthly cost, we can assume asystem life of 10 years, an interest rate of 8% peryear and maintenance cost of 10% per year, obtaininga monthly cost of 1/48 of capital cost. The monthlycost that goes with the capital cost figure of1110is then $2.29 per month per subscriber. If we assume80 hours per month-of usage by each terminal, theaverage cost per terminal hour is $0.03. If we assume40o hours per month of transmission on eadh channeland 24 channels, the average cost per channel hour is$2.38.

Two-way communication. New cable television sys-tems are now being installed with channel capacity forcommunication of data from subscribers back to a

1.6

computer at the head-end of the cable system (3). Pre-sent system designs permit a single camputer to collectinformation from as many as 10,000 users in less thantwo seconds (4). These same systems can automaticallyrecord_ whether the television set is on and what chan-nel it is tuned to. Figure 1 shows the network config-uration for this type of system.

The terminal configuration at the subscriber'send of such a system is likely to take the form shownin Fig. 2. In this configuration the house drop cableor cables are connected to a unit containing a modula-tor-demodulator (modem) and a digital memory. When asignal is received from the computer in the data chan-nel it is demodulated and, if the address is that ofthis terminal, the data signal stored in the memory isread out, modulated, and transmitted upstream to thecamputer. Subscriber data messages are written intothe memory through a 12-button pad. A paper tape re-corder may be used to record the subscriber's messageas he types them or to record acknowledging signalsfrom the computer.

The cost of a terminal configuration of thistype,apart from the television set, is in the range of $100to $300 depending on the detailed design requirementsand the quantity produced. We have estimated $200 forall items in Fig. 2 except the television set. Quan-tity production, on the order of tens of thousands ofterminals per year, is assumed. Additional costs fora two-way system of this type include the cost of areturn cable or upstream lowband amplifiers in theexisting cable plus the cost of a computer at the head-end for polling, data storage and processing printout.

CABLE HEAD ENDINCLUDINGCOMPUTER

TRUNK CABLE

IL 1. L L I. L

TRUNK CABLE

TERMINALS117±11.ousE DROP

FLIM/1/0110111MIIMMPIGOIT1 1 1iiii

AMPLIFIER {DOWNSTREAM)

AMPLIFIER (UPSTREAM)

Fig. 1. A two-way cable TV network.

TV SET

TWELVEBUTTONPAD

I

SNGLEFRAMEMEMORY

CHANNELSELECTOR

CONTROL' -P.

UNIT

PAPERTAPE

RECORDER

MOOEMAND

MEMORY

'MICROPHONE

HOUSEOROPCABLE

Fig. 2. Terminal configuration of a two-way cable TVsystem.

Table 1. Typical Hardware Costs in Dollars for Three types of Cable TV Systems(not including TV set costs).

CostCategory

Type ofSystem

CapitalCost perSubscriber

MonthlyCost perSubscriber

Cost perTerminalHour

Cost perChannelHour

MaximumNumber of.Simultaneous

Users

MaxiummNumber ofUser Termi-nals perChannel

MaximumNumber ofPictures

SimultaneouslyDisplayed

Conventional 24Channel One-WayTV (National 110 2.29 0.03 2.38 10,000 10,000 24Average Under-ground TrunkCosts)

Interactive TVwith SRS 320 6.67 0.07 6.95 10,000 10,000 24

Interactive TVwith SRS andSingle Frame

520 10.82 0.14

11.26

720 to 30 to '1 720 to0.04 toLocal Storage 0.37 7,200 300 7,200

We estimate $10 per subscriber for these items in a10,000 subscriber system of the type and density con-sidered above. When these costs are added to the one-way system costst the total capital cost per sub-scriber becomes $320.

Techniques such as those recently demonstratedin the Reston, Virginia cable system also permit'time-sharing' the cable communication capacity for analogdata (still pictures), with the television set be-coming a computer display terminal (5). Completelyindividualized computer-aided instruction, informationretrieval and other computer services can thus bebrought to every home. This technique, using a localvideo storage device, permits on-demand display ofdigital or still video messages transmitted fram acentral location at reasonable cost. The technologyrequired for this service Ls usually referred to asa 'frame7grabber because it takes a single televisionpicture (or 'frame') lasting 1/30 of a second, grabsit out of all the other frames being transmitted onthe cable, and then repeatedly supplies it to the setso that the viewer sees this frame as a still pictureon his set. The key component of such a system isthe unit that stores the frame locally. The systemdemonstrated in Reston utilized a commercially avail-able videotape recorder for this purpose. Other ap-proaches are possible, including storage tubes suchas the plasma display tube (6) and recirculating de-lay line systems using delay lines with delays of 1/30second or more.

A critical cost parameter in such a system is thenuMber of users that can share a Channel. If theaveraze time between frames for each user is onesecond, then the maximum number of users per channelis 30. If the average time is 10 seconds, 300 userscan share the channel. We have estimated $200 perterminal for a 'frame-grabber' that could be inte-grated with the digital audience response capabilitydiscussed above. The cost estimate for this type ofsystem is less certain than the other cost estimatesgiven here, because frame-grabber technology is stillin a state of rapid change. The cost per channelhour given in Table 1 is given first for this systemas'a cost for the channel as a whole and then as acost for an individual using the channel either 1/300or 1/30 of the time, corresponding to an average timebetween frames of 10 seconds or 1 second.

An information utility. The technical potentialdescribed above can make possible an information util-ity providing an individualized cammunication systemwith on'demand information storage, processing andtransmission capability (excluding motion video,

1.7

which would have to be shared with others at scheduledtimes). It may be visualized as a communication net-work providing access to a large nuMber of. retrievalsystems in which nearly all information, entertain-ment, news, library archives and educational programsare available at any'time to any person want7:,ng them

(7 ).The information utility is likely to be a series

of different overlaid computer-cammunication networks,some competing with one another to provide similarfunctions, others providing different functions. Theseseparate networks will share many of the same physicalfacilities, such as aser terminals, communicationlinesand a switching computer. It is likely that each dif-ferent network or service will have its own separatecomputer, central data file, and computer software.

References

1. Television Factbook, No. 40, 1970-71.2. W. Comanor and B. Mitchell, "Cable television and

the impact of regulation," Bell Journal of Eco-nomics and Management Science, 2, 154-212 (Spring1971).

3. S. Edelman, "Cable communications: Los Gatosexperiment," The Electronic Engineer, 32, 41-44(June, 1971).

R. Jurgen, "Two-way applications for cable tele-vision systems in the '70s," IEEE Spectrum, 8,39-54 (November, 1971).

4. R. T. Callais and E. W. Durfee, "The subscriberresponse system," Proceedings of the 20th NationalCable Television Association Convention (1971).

5. J. Volk, "The Reston, Virginia tent of the MitreCorporation's interactive television system,"Mitre Corporation Report, MTP-352 (May, 1971).

6. D. Alpert and D. L. Bitzer, "Advances in com-puter-based instruction," Science, 167, 1582-1590(March 20, 1970.

7. E. B. Parker, "Technological change and the massmedia," Handbook of Communication, in W. Schrammet. al. (Eds.) (Chicago: Rand McNally, in press).

12

THE FUTURE OF THE TELEPHONE INDUSTRY,

1972-1985

Andrew J. Lipinski

Institute for the Future2725 Sand Hill Road

Menlo Park, California 94025(415) 854-6322

Abstract

The paper summarizes the results of a study conductedin 1970-1971 by Paul Baran and the author, sponsoredby the American Telephone and Telegraph Company, toexamine the future of the telephone.industry. Vir-

tually all of the necessary information, largely judg-mental, was obtained from panels of experts, who inter-acted anonymously through a series of questionnairescirculated through the mails. Two hundred ten expert"respondents" were selected individually for theirpersonal technical knowledge and not as representa-tives of any organization. They came from a largenumber of organizations, including the Bell System.The conclusions of the experts deal only with proba-bility of developments, rather than with theirdesirability or lack of desirability. In very gen-eral terms, the findings suggest that the future ofthe telephone industry appears secure. Major growthis anticipated in many sectors of the business, andthe services provided by this industry are not atvariance with the long-term goals and needs of anymajor sector of our society.

There are, hou.7.ver, some changes on the horizon,almost all originating outside the telephone indus-try. These are (1) Tmovement to a form of competi-tion in some sectors of the business, (2) shifts in

the nation's value system, (3) an under-current ofpublic dissatisfaction with all industries, especiallythe more regulated ones, and (4) increasing adversaryencounters with some previous supporters of the tele-phone business. The fundamental changes seem to hingeon the redivision of power among various sectors of

society. It seems likely that the telephone industrywill be able to live with the changes which appear tobe coming down the road--but.with varying degrees ofcomfort.

Paul Baran and Andrew J. Lipinski, The Future of theTelephone Industry, 1970-1985, Institute for theFuture, Report R-20 (September 1971).

38

A REQUIEM FOR ANALOG DATA STORAGE

M. 0. FelixAmpex Corporation

401 BroadwayRedwood City, California

(415)367-3927

The supreme success of digital techniquescomes from the speed and accuracy with whichthey can process data. Why then are theusers of business EDP systems so often frus-trated by the mountains of output that seemnecessary to obtain a few key facts?

One reason is that the digital strengths inprocessing have hidden the two weaknessesof digital storage. First of all, digitalstorage is expensive. It is true a bit maybe stored on tape for 10-6 cents but a bitis a very small amount of information. Asingle 8-1/2 x 11 inch page can hold severalmillion bits, and so cost several cents tostore. Since business files often contain107 to 108 pages, these costs become major.

Therefore, usually without realizing it, theassumption has spread that all informationmay be abstracted and that only this smallpart of the original need be stored. Now,with 4,000 characters to a page, the numberof bits has been cut 100:1 and digital stor-age becomes economical. But it is thisabstracting process that is the Achilles'heel of EPD systems, for all too often it isthe rejected piece of information that con-tains the odd fact that later is the key towhy the process failed. In trying to preventthis, more and more information is abstractedand, worse still, more and more must be pre-sented to the eventual user.

Analog storage attacks the problem from theother end. All is stored, at very low cost,and with tremendous (visual) redundancy.Error rates, by digital standards, may beabsurdly high. One error in 106 is perfec-tion and one in 103 is quite usable. Storagecosts of 0.2 cents per 8-1/2 x 11 inch sheetare history (either on magnetic tape or film),and further reductions are already possiblein the laboratory.

One may object that the output of such asystem is cluttered with evan more redundantinformation than the digital; however, theform this redundancy takes is often verydifferent. The brain's ability to detectpatterns, or to pick out the odd element,whether it be one number or one fingerprintout of thousands oi similar ones, has yet tobe equalled by a machine.

Thus, both analog and digital storage systemshave their places:. the analog where theemphasis is on storage, and where the riskof abstraction is high; the digital wheredata processing is the key. Business files,fingerprints, photographs, and medicalrecords are good examples of where the lossby d±gital abstraction or conversiongenerally far outweighs any gain from theability to P rocess the information.

PATHS TO AN INFORMATION UTILITY:An Introduction to a Seminar on

Applications of Computer Communications

E. M. Van VleckResearch ScientistNASA - Ames Research CenterMoffett Field, California 94035Tele: (415) 961-1111, Ext. 2133

What is happening in computers and communica-tions has been called an "explosion," a "revolution,"and a "discontinuity." Where this joint revolutionis heading has been called "instant world," "electricsupermarket," "wired nation," "information utility,"and "global village." Even these broad terms may betoo definite since, as Gordon Thompson points out,"the assumption . . . that we really know what we arebuilding is essentially groundless."

It is quite clear, however, that wherever thingsare headed, the progression will be through specific,discrete applications involving the major "revolu-tionary" elements, of which four immediately standout. There is a revolution in the complexity ofsocio-technical problems and probably the beginningsof a user revolution: Confronted with proliferatingnew "post industrial" problems, users are beginningto search actively for suitable new information tools.The well known "computer revolution" and the "communi-cations revolution" are perhaps finally ready to beforged into just the kind of powerful informationtools needed by users to cope with the "problemrevolution."

This conference occurs at a good time to examinethe confluence of these four revolutionary streams,and to examine: the general trends and specificapplications driving computer communications forward;the hurdles to be encountered and the means of sur-mounting them; and the social problems of "wiring anation for computers."

The papers in this Applications Session typifyinteractions between system elements likely to beinvolved whatever exact form information utilitiesmight eventually take. Hopefully a mere handful ofselected papers may nevertheless represent a broadrange of specific problems, user communities, com-munications media, and computer applications. The

topics include: medical databanking over a terres-trial/space satellite communications network; widebandsatellite interconnection of widely separated com-puters; digital interconnection of inflight aircraftwith an air traffic control computer system; satel-lite linking of pupils in remote Indian villages tothe computing power of a large university computercenter for computer assisted learning; the merger of

video and computer technology in Instant RetrievalTelevision; and computer communications projects ofone of the Nation's largest information handlingorganizations--the Post Office Department. A fur-ther paper surveYs several important applicationsnot separately included in the selected sample.

The broader questions such as ultimate forms of

the information utility, and its evolutionary adapta-tions to social re'sistance must be left to other ses-

sions. This session concentrates on specific casesthat indicate the rich variety Of ways that the four

"revolutionary" themes may be orchestrated.

2.1

The abstract debates and studies of ideal futuresystems will continue, but meanwhile the systems ofthe future are being incrementally built throughspecific applications such as these.

The likelihood that an ideal computer communi-cations system will merely evolve without consciousexternal direction appears slight, and there is asyet little evidence either of a social agency capa-ble of providing such direction or the national willto exercise such control.

The future computer communications network willnot be "Systems Engineered" as the telephone networkhas been, for example. Therefore, we must hope thatnumerous applications such as in this session willprovide a broad spectrum of technological capabilityand experience so that unpredictable social resistancecan at least be approached with a degree of techno-logical flexibility. In this way, in the absenceof other clear goals, future national informationsystems may be realized that are "transparent," inthe sense that they are at least not extremelysocially-distorting.

14

A NATIONAL BIOMEDICAL NETWORK

By J. E. Burtt, Staff Engineer, Lockheed Missiles &Space Company, Dept. 64-60, Sunnyvale, California,94088, Telephone (408) 742-8088.

Presently there is not a formal plan by responsiblegovernment agencies and medical centers for a nationalhealth care or biomedical communications network forexchanging television and computer data betwct nmedical centers.

The requirements and costs of a communicationssatellite to provide a national health network for bothmetropolitan and isolated users is beir,g study byLockheed Missiles & Space Compaig under a contractto NASA's Manned Spacecraft Center at Houston, Texas.The growth of local and regional data communicationsnetworks throughout the nation (16 systems are inexistence) and the growing use of automated datasystems at medical centers are providing the elementswhich could be interconnected to fortn a national bio-medical network. Such a network would benefit thegeneral population and the medical community. Thebenefits of such a network increa ee. tremendously withthe growing use and sophistication of biomedicalcomputer systems and automated equipment.

A brief review of the present status and benefits pro-vided by the key elements available for such a networkprovides insight into the future uses and expectedbenefits and problem areas.

Special Purpose Computers

Special purpose biomedical computer systems such asthe AML facility at the Palo Alto Medical Clinic canprovide biomedical data in a form fully compatible witha data network. The AML system collects and forimi-lates the patient's medical history and problems byasking questions through a visual display terminal.Patient response is by push button selection. Semi-automated sensors provide data inputs to the computerand special data can be entered by the medical techni-cian. The completed, typed medical history and reportof the medical examination is available upon completionof examination, which takes approximately 45 minutesper examination. Presently the typed medical recordis sent to the requesting doctor by courier or mail.The record could be stored and transmitted by networkto the doctor within seconds when requested forreference or update.

Extensive use of such equipment and a national networkcould eliminate the repetitious, costly collection andmanual updating of medical histories. Most medicalhistories formulated today are based upon the patient'smemory and understanding (or misunderstanding) of hispast medical history. Personal medical historiescould be formulated from successive inputs to medicalterminals and would provide an accurate professionallyprepared and documented history. Data banks ofpersonal health records presently provide a researchtool for studying national and regional health problemssuch as effects of pollutants. Available telecommunica-tions and automated data systems can provide betterhealth records for a fast paced mobile society.

General Purpose Computers and Teleprocessing

Present hospital information systems using generalpurpose computer and software systems provideimproved financial and biomedical record keeping and

monitoring of patient treatment. Teleprocessing isproviding quick response analysis of biomedical data suchas electrocardiograms.

Television

Television is being used to provide improved medicaleducation, consultation, and aid to patients remotelylocated from a medical center. The use of televisionalso provides quick access to the doctor in emergenciesand a saving of travel time.

Display Terminals

The Lockheed Missiles & Space Company has assembleda medical data display console for demonstrating themeans and effectiveness of selecting and examining datafrom remote sensors and data banks. The doctor cancommunicate with patients at remote locations on tele-vision, obtain and analyze biomedical data obtained fromremote sensors, and order and examine selected historicbiomedical data from microfilm or computer data banks.Heal-time and historic data can be displayed in formatswhich are convenient for analysis. The console repre-sents the next step in the use of communications andcomputer systems for improving health care of isolatedpatients or consultation with a remote medicalspecialist.

Communications Satellites

NASA's ATS-1 satellite is being used by the Universityof Alaska and Stanford University to provide improvedmedical aid to 24 remote villages in Alaska. Each ofthe remote villages utilizes the satellite for scheduledor emergency verbal communication with doctors atthe University of Alaska. The doctor gives directionand instruction to a medical aid who treats the patientand observes the patient's condition. The system iscredited with preventing deaths in emergency situationsat isolated villages.

The next generation of communications satellites suchas the proposed MCI Lockheed domestic communica-tions satellite will be nonspinning, three axis stabilizedand capable of providing over four times the communi-cations capacity of present operational satellites. Asthe capacity, reliability, and expected operating lifeare increased, the cost of long distance television andcommunication links to remote areas will be reduced.

Problem Areas

One of the major problems in using the availableelements to form a network may be the growing useof computers without a formal plan for a national net-work. The lack of computer interface and data formatstandards severely limits the machine to macsineexchange of data between medical centers and hospitals.As each of seventy-five major medical centers in thenation utilizes one or a combination of several avail-able computer systems and makes in-house modifica-eions of system programs to suit local preferencesfor format and nomenclature, it will become difficultfor a center to exchange machine data with each of theother 74 individualized medical centers. Approximately7,000 hospitals and clinics in the nation could benefitfrom remote terminals providing access to theregional medical libraries, laboratories, medicalschools and data banks of a national network. Withoutplans or incenfives for regional or national networks,hospitals may obtain equipment which best meets themost pressing in-house needs at a minimum cost withoutregard to the future benents or costs of converting

2.2

15

equipment and modifying software for operation on anational network.

If firm plans for the development of a national healthnetwork are delayed for several years, options forsatellite orbit stations and operating frequenciesbecome progressively limited due to the progressiveestablishment of other networks using the communica-tions nets provided by satellites. Only a limitednumber of synchronous satellite operating stationsare available along the sector of the equator whichallows coverage of the United States, Canada, Southand Central America. The available satellite stationsmust be shared with other nations. Internationalcommunications satellite traffic has been doublingevery three years. Such a growth rate for satellitesproviding communications over the Western. Hemispherewill create an eventual shortage of satellite communi-cations. How and when the shortage will occur dependsupon future frequency allocations and technical pro-gress in the reuse and conservation of radio frequencybandwidth.

FAA's "IDIIOM" AIR TRAFFIC CONTROL SYSTEM.J-C-Ic O. Thomas, Federal Aviation Administra-tion, Oakland Air Route Traffic Control Center,5125 Central Avenue, Fremont, California 94536,(415) 797-3200, X302.

The name IDIIOM, acronym for Information Displays,Incorporated (of Mt. Kisco, New York) Input Out-put Machine, has become associated with a projectof the Systems Research and Development Service ofthe FAA to evaluate a computer generated visualdisplay of long-range over water flight movements.Tests are being conducted at the Oakland Air RouteTraffic Control Center, controlling facility forairspace overlying approximately 31/2 millionsquare miles of the eastern Pacific. Flightoperations within that oceanic area totaled95,366 during calendar year 1971.

Flight plans and movement reports are processedthrough a Varian mini-computer which generatesboth a graphic picture of aircraft position,identity and movement, and a tabular display ofinformation quite similar to that used in con-ventional non-radar air traffic control.

Displays consist of two 21 inch cathode ray tubesmounted in consoles adjacent to the facility'soceanic control sectors. A function keyboardand a light pen give the operator a wide rangeof display selectivity. An ASR-35 teletypewriterprovides means for input into the computer ofmovement messages received at the operating po-sition.

On the graphic display, background mapping si-milar to radar video mapping is portrayed. Thearea displayed is merely a function of computerprogramming and is easily changeable. A normalsetting to show the most heavily traveled routesbetween the West Coast and the Hawaiian Islandscovers that portion of the Oakland Center'soceanic control area between the 24th and 48thparallels and from the West Coe5.0- to the 145thmeridian. However, through a zooming technique,one degree of latitude and longitude can be ex-panded to cover the entire screen. Such a tech-nique might be used to focus on an area of im-mediate interest or aircraft emergency.

Two methods for displaying aircraft movement arebeing evaluted. The first applies to a limitednumber of Boeing 747's equipped with data linkwhich relay aircraft identification, positionsas aetermined by inertial navigation and actualaltitudes reported in 100 foot increments. Thelink between aircraft and the controlling fa-cility is provided by Aeronautical Radio, Inc.(ARINC) using a high gain troposcat antenna.Aircraft involved in the test respond in se-quence to the VHF pulse with the individualquestion and answer cycle being completed in 55microseconds and repeated each 32 seconds. Datareceived through the relay is analyzed and air-craft positions are displayed in their properrslationship to the background mapping. Associ-ated with each target symbol is a small signidentifying in alpha numerics the aircraft andits altitude.

The second method called correlation is used todisplay position and movement of aircraft notequipped for data link relay. Flight plan in-formation including aircraft identity, type,speed, route, and altitude are first fed into

.the computer then activated by a position report at a fixwithin the oceanic sector. From that data and applyingenvironmental information such as predicted winds aloft,the computer determines aircraft position in a manner com-parable to pilotage-by-"dead-reckoning". Aircraft iden-tities and altitudes are displayed as alpha numerics in amanner identical to that used for aircraft reporting throughdata link while the use of different target symbology pro-vides a visual differentiation between the tWO methods ofreporting. Target positions are updated at 2-minute inter-vals, and when routine position reports received throughnormal radio channels are fed into the computer, the targetposition and track is updated to reflect the reported loca-tion and recomputesl_ground speed.

Additional features include:1. Velocity vectors associated with each target symbol in-

dicating the direction of flight of the aircraft andits estimated progress within the succeeding 5 minute,10 minute, 20 minute or 40 minute interval as calledfor by the controller.

2. Notification by a printout of the word LATE that a re-quired position report is overdue.

3. A reminder by printout of the word HAND that an air-craft is approaching a jurisdiction boundary and thatcontrol responsibility should be released to a neigh-boring facility or sector.

4. A warning of possible loss of standard lateral or longfrtudinal separation between aircraft at the same alti-tude. This warning is indicated by a printout of theword CONFLICT in the lower lefthand corner of the gra-phic display and associated with the warning is theidentity of all aircraft involved. In responding tothat warning, the operator can call for route projec-tion to show the point and time of conflict. From thatinformation, the operator can make his control decisionand can test his decision for validity by querying thecomputer for any additional conflictions which mightresult from a change of altitude, route, or speed onany or all of the flights involved. In such tests, thecomputer will indicate CLEAR or will print out new con-flictions which would result from the proposed controlaction.

5. Special activity airspace may be electronically tracedon the face of the graphic display. Such area descrip-tions serve as a warning and simplify procedures forsegregation of airspace reserved for special militaryactivity, missile impact, etc.

6. Computer programming established acceptable parametersfor position reports, pilot estimates, and reportedaltitude. When information exceeding those parametersis received by the compute it suggests that the con-troller question the validity by printing the letterV adjacent to the aircraft identification.

The tabular display gives statistical information. It canbe called upon for complete flight plan information. Inaddition, it displays for all aircraft within the selectedenvironment columnar groupings of:1. The identity of each aircraft.2. The last reported position (fix) shown in latitude and

longitude or by designated fix name.3. The time the aircraft was over that fix.4. The flight level - actual when reported through data

link.5. The identity of the next reporting point.O. The computr estimate at the next fix.7. The pilot est....date at the next fix.8. Ground speed, continually updated as each position

report is received.9. The Present position in latitude and longitude reported

to the nearest minute.

Additionally on the tabular display, the alert features,including notification or warning of potential conflic-

2.4

tions, overdue position reports, pending trans-fer of jurisdiction or need for verification, arehighlighted. This is accomplished by removingfrom the total grouping the line/s of data re-lated to the aircraft in question.

The oceanic displays are not commissioned for airtraffic control use and priority must be givento the t!st and development project. However, inlimited applications to "live" traffic thismethod of visual presentation has provided gra-tifying support to the ongoing operations.

Controllers at oceanic positions using standardnon-radar technique have used the display to con-firm their own judgment. When changes of routemay be needed, course information and targettracking provided by this equipment is far su-perior to the grease pencil and piece of stringwhich must often be used in outmoded controlmethods. The displays have proven a distinctadjunct to the facility's Air Movement Informa-tion Service (AMIS) giving a continually updatedpicture of aircraft approaching an Air DefenseIdentification Zone (ADIZ) or operating withinthe ADIZ.

The equipment has been used as a briefing devicein preparing for large scale military exercises.Pending missions have been entered into the com-puter and the entire air movement previewed vis-ually in fast time by the controllers who will beinvolved in the exercise. Aircraft in militarymissions proceeding well beyond the limit ofcoastal radar have been "tracked" through theuse of computer generated targets using thecorrelation method. This technique has greatlysimplified re-identification of aircraft ap-proaching the coast line and can often lead toa more efficient use of airspace.

As a research and development project, the im-mediate goal is to evaluate the display systemas a control device. Available equipment hasalso been used for limited tests in the use ofdata link for relay of air traffic ciearances.There are plans for evaluating a wide-screendisplay of oceanic traffic. And there is hopethat the Oakland Air Route Traffic Control Centermay be involved in early te:ts of the use ofsatellites in the relay of air traffic communi-cations and movement.

In pursuing the long-range goal of continuallyimproving air safety and service, there is con-siderable optimism that the technique of re-ceiving and displaying.flight movement informa-tion without the limitations of land-based radarmay prove the answe*L to the problems in handlingthe steadily increasing volume of oceanic traffic.

2.5

18

EXPERIMENTS WITH SATELLITE DISTRIBUTION OF

COMPUTER ASSISTED INSTRUCTION

by

John Ball and Dean Jamison

Institute for Mathematical Studiesin the Social Sciences

Stanford University, Stanford, California 94305

The Institute for Mathematical Studies in theSocial Sciences at Stanford University maintainsa large interactive computing system. It is usedprimarily for research and application in thearea of computer assisted instruction. Thismeans that in th r.f. research area the Institute istrying to define algcrithms for learning and inthe applications aree the Institute supports alarge timesharing conputing system on which manystudents receive a 7)art of their instruction.

The IMSSS system at present supports 11 highspeed graphic terminals, 6 oedium speed CRTterminals, 225 teletype terminals and a varietyof other equipment. The teletype terminals arelocated at over 20 locations throughout theUnited States. This large terminal networkrequires a correspondingly large effort in datacommunication by IMSSS in addition to supportingthe time sharing system necessary for upwards of125 on-line users.

The data communication system servicing theseterminals is conceptually simple. As seen inFigure 1 the High Speed Line Multiplexor is awired program camputer which communicates withthe timesharing system on the one side throughcore memory buffers and with devices on the otherside through individual High Speed Line Units.Outputs of the High Speed Line Units-can beadjusted to fit the needs of the ,attached dataequinment.

For example, high speed graphic displays canbe operated with 9600 baud serial asynchronousdata output while remote multiplex computersrequire a 2400 hand synchronous interface to alocal data set. The remote multiplex computerthen reduces the 2400 band stream to individual110 band Teletype channels. A particularlydifficult problem in this data communicationnetwork is an installation of a small number ofterminals, say 2 to 8 in an elementary school.Most approaches to maintaining a data camm linkof that length and cluater size seem veryexpensive in relation to the other costsinvolved.

One approach to this problem which IMSSS isnow trying is the use of a duplex satellitechannel and a loi cost ground station for thedata communication link between Stanford andan elementary school at Isleta pueblo, NewMexico. Figure 2 diagrams the use of ATS-3

on a duplex communication channel. The data signalsinvolved are frequency shift keyed analogues of thevoltage mode teletype signals in a 500 to 3000 Hz band.

RF transmission uses the GE MASTR ground stationwith a power output of 350 watts and is in the 2 meterband from 136 to 149 MHZ. Yagi antennas have beenused in single, dual, and quad configurations aswell as a single helix.

At this writing the system is not fully operational.Factors contributing to the present status include halfpower mode operation of the satellite, limitedsatellite time available for testing, receiverdesensitization, antenna pattern and pointing, antennaloading, polarization variables, spin stabilizationvariable, and random problems that are not understood.

There does not, however, appear to be any reasonwhy successful operation can not be achieved.Calculations show a theoretical S/N of about 24 db forthis link. On rare accessions this has been approached.Typical S/N figures range from 12 to 17 db. The linkshould be in regular operation (1-1/2 hrs per day) byearly spring of 1972.

In conclusion we would to mention the relationshipbetween our experiment with the ATS-3 and our longerterm efforts to provide students with interactiveinstruction at reasonable costs. In an earlierpaper--Jamison and Ball [1971]--we examined theconditions under which satellite distribution of CAIwould be cost-effective with respect to commercialphone distribution. As one would expect, satellitesappear cost-effective only when terminals are highlydispersed and at reasonably large average distancesfrom the central camputer facilities--more than 300to 500 miles. These conditions are met if one wishesto utilize the flexibility, curriculum diversity, andeconomies of scale of a large computer and if thedispersion of CAI with time is somewhat geographicallyhomogeneous. Thus in the evolutionary stage betweenthe present time, where there is virtually nooperational use of CAI, to the time when it is astandard part of every student's education there wouldappear to be an important potential role for satellites.Our present experiments are aimed at increasing ourunderstanding of that role, and at gaining experiencewith the problems that must be resolved before anoperational system is possible.

Reference

Jamison, D. and Ball, J. "Communication economics ofinteractive instruction for rural areas: Satelliteversus commercial telephone systems." Paper presentedat the XXIInd International Astronautical Congress ofthe International Astronautical Federation, Brussels,September 1971.

(Figures on next page.)

2.6

Figure 1

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2. 7 20

INSTANT RETRIEVAL TELEVISION: FROM THEORY TO SYSTEM

L. H. DayStaff Supervisor - Business PlanningBell Canada620 Belmont, Room 1105Montreal 101, Quebec, CanadaTelephone: (514) 870-3223

Introduction

Computer communications in North America iscurrently undergoing a revolutionary change which isreflected in the title of this conference. Recentexamples of events accelerating this change include:

the FCC computer communications inquiry- the "Rostow" commission- the Telecommission in Canadathe Carterphone decisionthe birth of specialized common carriers

- development of digital networksthe Canadian Computer/Communications Task Force

- the deveIopment of powerful, low cost mini andsmall computers

- increasing attacks on "fortress I.B.M."

These events have impacted mainly on two aspectsof computer communication:. They will result in asignificantly changed structure of the industry andits regulation. There will also be significant in-creases in the type and quantity of computer communi-cations capabilities available through the rapidIntroduction of newer technologies and new entrantsinto the industry.

All of these changes have been debated in recent

years in many public forums and their prominence has

tended to overshadow another aspect of rapid change

in this field. This is the changing character ofcomputer communications system applications. Until

recently most systems consisted of automating or

speeding up an existing operation by fitting the

applications to a few basic models. We are now

rapidly reaching the point where systems applica-

tions can be designed around the user's require-

ments and not around the available technology.

User Needs Research

The revolution in system applications will notarise only from changing technology but also from abetter understanding of user requirements. Thisunderstanding can only develop through new forms ofresearch and analysis. This includes basic researchusing theories of the utility of communications sys-tems and it also includes research into future systemsrequirements. This paper overviews some Canadianresearch in these areas and described one system thathas evolved from this type of research - InstantRetrieval Television (IRTV).

Communications Jtility Theory

Gordon Thompson of Bell-Northern Research inOttawa, Ontario has developed three measures of com-munications effectiveness. These measures are:

- the ease with which stored human experience canbe accessed.the size of the common information space sharedby the communicants.the ease with which the society using th, systemcan discover and develop a plurality cf new andfresh consensus (1) (2).

Thompson's research has found that the highera system or technological package measures on thesethree scales, the greater its benefit to its' usersand the more widespread its' adoption amongst poten-tial users.

Delphi Studies

Thompson's theory helps provide a means ofevaluating new potential systems. The generationof applications concepts to test comes from varioussources. One important source of concepts for BellCanada has been a series of Delphi studies conductedby its Business Planning Group over the past threeyears. These studies have explored the future needsfor computer communications and visual communica-tions systems in the Educational, Medical and Busi-ness fields (3) (4) (5). A current study is examin-ing the future of communications services in thehome (6). This data provides further guidance inthe development of potential applications systems.This work is oriented towards developing future sys-tems. One system that has been developed and testedextensively in the past three years in Ottawa,Ontario is Instant Retrieval Television (IRTV - alsoknown as Information Retrieval Television).

I.R.T.V.

I.R.T.V. is a- educational system using acentral Retrieval ter, housing a large (2,500-10,000 titles) liblary of visual material and acoaxial cable distribution system which is linkedto television sets in individual classrooms orteaching areas. A teacher can order a title from aspecial classroom telephone and have it displayedimmediately, or schedule it for a period later inthe day or week.

The essential difference from normal E.T.V.systems is that the user (teachers and students) canutilize a large bank of material on demand. Theycontrol the system. They do not have to organizetheir activities around the system's schedule.

System Evaluation

When the system is evaluated using Thompson'smeasures it rates highly on all three scales. TheDelphi panel has also predicted wide scale adoptionof this type of system over the next 15 years. Thestudents and teachers also rate the scheme highlyand have been enthusiastic supporters of the threeyear experiment.

Conclusion

The development of Thompson's theories, theDelphi studies, and the I.R.T.V. experiment are goodexamples of how user needs research and developmentof practical user systems can be blended. BellCanada, BNR, the Trans Canada Telephone System andselected users are currently cooperating to developand trial other systems that utilize and refine thisapproach.

References

1. Gordon B. Thompson, "Moloch or Aquarius?", The,Issue 4, February 1970.

2. Gordon B. Thompson, "The Greening of the WiredCity," Telesis, November 2, Summer 1971.

2.8

21

3. Frank J. Doyle and Daniel Z. Goodwill, "AnExploration of the Future in Educational Tech-nology," Bell Canada, January 1971.

4. Frank J. Doyle and Daniel Z. Goodwill, "AnExploration of the Future in Medical.Technology,"Bell Canada, March 1971.

5. Daniel Z. Goodwill, "An Exploration of the Futurein Business Information Processing Technology,"Bell Canada, October 1971.

6. Michael Bedford, "The Future of Communicationsin the Home," (Delphi questionnaire), Bell Canadaand McGill University: November 1971.

7. Trans Canada Telephone System, "Computers,Communications, and Canada," November 1971.

2.9

22

EVALUATING COMPUTER APPLICATIONSRoger W. Hough

Stanford Research InstituteMenlo Park, California

Introduction

Previous papers in this session have discussedapplications of computers and communications thatmay be characterized as experimental or still in thedevelopment stage. That they represent services ofthe future cannot be doubted. However, in assessingthe likelihood of the extent of future applicationsone often finds it difficult to separate good ideasfrom marketable ones.

The objective of this paper is to attempt toput computer-communication services into perspectivesomewhat, by concentrating on on-going applicationsand derivatives or extentions thereof. This can bedone in a variety of ways, for example, by identify-ing, classifying and enumerating various communitiesof users, by differentiating present from futureapplications, and by analyzing those communicationsmedia that are applicable to each class of servicesand/or users. Each of these is briefly touched onin this discussion.

User Communities

The spectrum of users of computers and communi-cations now covers virtually every one of the majorStandard Industrial Classifications (SIC codes) ofthe U.S. Department of Commerce. These range fromagriculture and forestry, to durable goods manufac-ture, to wholesale and retail trade, to financialservices, government, and so on. Many of the cate-gories are represented only in a small way, being sofar only minor participants in the new online, realtime, remote terminal revolution. Other categories,however, such as transportation, banking and finance,and securities brokerage constitute industrial group-ings that make up a large fraction of the totalusage. (We do not ignore here the extent of theFederal Government's participation, particularly DoDand NASA. Our emphasis, however, is on commercialapplications.)

In early 1968, approximately 60,000 data setswere in commercial service. In early 1970, this num-ber had increased to 140,000 representing a growthof 50% annually. Such increases have continued,though at lower rates of growth, despite the 1970-71business decline. At present, some 250-300,000 datasets are in service, increasing to about one millionby 1975.

Overall, approximately the same number of ter-minals are in service as modems or data sets. Cur-rently these also amount to about 300,000, and theyare connected to some 8,000 to 10,000 general purposecomputers through a great variety of network config-urations and telecommunication links. Many of thesecomputers have only a few terminals, and in somecases they are little used. In other situations,however, the terminals are an integral part of areal time information system that operates on "live"business data. Airline reservation systems, stockquotation systems, and certain banking operationsare a case in point.

As an example of the extent to which computer-communications can permeate business activities, we

2.10

refer to a previously compiled list of some 300 pot-ential data transmission applications classified byindustry. Table 1 summarizes this list, givingthe number of potential applications identified foreach industrial grouping. Table 2 illustrates someof the applications.

2 3

Table 1Potential Computer-communication Applications

Identified by Industry

Industry Number

BankingInsuranceLaw enforcementLibrary servicesEducationInvestment and securitiesbrokerage

ManuThcturingPrinting and publishingPetroleum and industrial chemicals

processingWholesale and retail tradeUtilitiesTransportation

AirRailHighway

Medical/healthPersonal servicesTravelSports/entertainmentHome communications

Table 2Example Applications

BankingDemand deposit accountingSavings accountingMortgage accountingCredit card accountingLoan accountingCredit authorizationsAccount balance inquiryOnline CuaLumer servicesOnline transaction entryAutomatic loan paymentsLock box remittance

Library services

24

1017

21

18

241813

14

1532

19

1S

18

18

64

6

Remote browsingInterlibrary loansAutomatic catalogingResearch and location of materialAnswering reference questionsDistribution of reading listsAccess to documents at remote locations

EducationInstructionInstructional managementTestingCounselingAdministrative planningConnecting remote campusesPlacement serviceFiscal accounting and reportingComputer assisted instruction

Present versus Future Applications

In this paper we are limited to giving onlybrief examples of the difference between present andfuture applications. These should illustrate twopoints, however, namely that one needs, on the onehand, V-- be cautious about projecting developmentsin certain (public) application areas, yet on theother hand not timid in assessing the likelihood ofdevelopments in commercially acceptable projects.

A case of the latter may be found in commercialbanking. At the present time, the bulk of the comp.-ter transactions taking place here are accomplishedin a batch mode, and this applies whether or not com-munication links are used. That is, most banks withgeographically dispersed branches transmit data "inbulk" via high speed links (19,2 or 40,8 kilobitsper second), process it remotely, then return thecomputed results in a similar manner. In California,where statewide banking is allowed, this practicehas led to the use of leased Telpak channels that,for the most part,double as voice lines as well asdata channels.

What is new on the banking scene is online, realtime, transaction-oriented processing. While suchactivIties have been underway for some time in mutualsavings banks and savings and loan institutions (atpresent, between 15,000 and 20,000 terminals are in-stalled in such locations), real time operations arestill in the future for most commercial banks. Thus,while demand deposit accounting is the first andmost obvious application that one would like to im-plement, the difficulty of doing so on a large scaleposes severe problems. Nevertheless, this kind ofcomputer-communication is inevitable and indeed isalready occurring on a small scale, as for exampleat Pacific National Bank in Tacoma, Washington.Here, Courier terminals--one terminal for each twotellers--are being used to access online customerfiles for inquiry as well as "store and hold" updat-ing, for both deposits and check cashing. At a14ri.er date, the growth of a direct funds transfersystem (the cashless society) is entirely feasibleand some observers are predicting it to be substan-tially in being by the end of the decade. Indeed,the acceptance of magnetic ink character recognition(MICR) was adopted surprisingly swiftly, there beingan elapsed time of only eight years between initialuse and 95% adoption of the technique.

In contrast to the above, one may take theclassic example of computer assisted instruction.While the potential of CAI has been pursued vigorous-ly for many years, its development to this time hasdepended largely on public funding, institutionalgrants, and so on. Thus, at this juncture one can-not say with certainty that its full development isinevitable. One can say that it is desirable, how-ever, if he chooses to do so, and I do.

Transmission Media

It is in this area that much controversy hasbeen generated. The fact that the telephone networkwas "initially designed for voice transmission" Lasled many observers to conclude that it cannot--evenwill not ever--be used effectively to transmit data.

-The facts of the matter significantly contra-dict sucll conclusions, however. First of course isthe simple illustration that data is (are?) trans-

2.11

mitted over the voice network, all day, every day,and with useful results. Despite all the handwringing over noise, errors, signaling, connectiontime, limited transmission speed, and so on, arecent survey of large telecommunications users,both voice and data, revealed only a small samplingof dissatisfied telco customers. The majority,surprisingly enough, have had excellent results,except of course in New York City where everything,including telephone service, is in serious difficulty.Naturally these customers would like to pay less fortheir service, but that is a separate issue fromservice satisfaction.

Of greater significance than present-day usage,however, is the situation likely to obtain in thefuture regarding transmission media. Here, thevariety of potentially competing systems are impor-tant, such as fully digital networks (e. g, Datran),other specialized carrier microwave systems (WCI etal), cable television, and satellites.

It is the author's contention that most uses ofcomputers and communications for at least the next15-20 years will take place over the telephonesystem. The reasons for this argument are as follows.First, it can be shown that the volume of transac-tions to be expected over such a time period is sig-nificantly less than the capacity of the network asit may be expected to develop. Second, present usesof the network are for the most part extremely in-efficient. This is changing gradually as users becomemore sophisticated in designing their own computernetworks which, in turn, use telco links for trans-mission. An example here is the expanding use ofminicomputers for data concentration and front end-ing. Third, most large users do not lease linesfor the exclusive use of data transmission. Rather,they use these lines in an alternate voice/datamode, often transmitting data at night and using thelines for voice transmission during the day. Inthis way, data transmission comes along for no morethan the cost of modems and associated equipment,excluding the cost of leased lines. Finally, onecannot overlook the ubiquitous nature of the tele-phone system--it is not only "there," but here,there and everywhere as well. Such coverage of thenation cannot in any way be duplicated withoutspending extraordinary amounts of money, regardlessof the fact that new (particularly digital) technol-ogy reduces significantly the investment requiredper bit transmitted.

Reference

1Hough, R. W., Carolyn Fratessa, Virginia Holley,

A. H. Samuel and L. J. Wells, A Study of Trends inthe Demand for Information Transfer, Stanford ResearchInstitute, Menlo Park, Calif., February 1970.

24

COMPUTER COMMUNICATIONS APPLICATIONSIN THE U.S. POSTAL SERVICE

Dr. Joseph V. J. Ravenis IIElectro Dynamic DivisionGeneral Dynamics CorporationSan Diego, California 92112Tele: (714) 279-7301, Ext. 2544

The United States Postal Service is the largestsingle business organization in the world, and dailyprocesses almost as much mail as the rest of theworld combined. If the system were to stop for oneday, every citizen and business in the country wouldbe affected. Unlike other business organizations thatcan stop production or cease operation for extendedperiods of time without adversely affecting thenation, the Post Office Department cannot. Forexample, over 30 million people depend on the PostOffice to deliver their monthly Social Security orretirement checks. To provide dependable service forthis ever-increasing tide of mail requires that thePostal Service modernize and become more efficient.

However, the utilization of technological ad-vances in postal long-range planning has been minimal;research and development on applicable methods andequipment to speed mail processing and reduce handlingcosts have been almost non-existent, until recently.

The Postal Service utilizes three systems totransmit data between major post offices, PostalData Centers (PDC's), Automatic Data ProcessingCenters (ADPC's), USPS Headquarters, and specialactivities. One is the Postal Source Data System(PSDS) network which interconnects major post officesto two ADPC's through four teleconcentrator points.The network consists of a variety of communicationterminal devices linked to Control Data Corporationcomputer equipment using AT&T and Western Uniontransmission facilities. Eighty cities are connectedby 110,000 miles of dedicated full:duplex 2400 bpslines. Over 8,000 terminal devices, such as trans-acter consoles, badge readers, and electronic weightscales are on line to five teleconcentrator sitesequipped with dual CDC 1700 computers. The fivesites feed into the two ADPC equipped with dual CDC3300 computers.

Another smaller network of magnetic tape termin-als transmits data between USPS Headquarters, sixPDC's and two ADPC's via Digitronics equipment anddial up voice grade AT&T common carrier transmissionlines (203 A modems).

The third network connects two supply centers insupport of the realty logistic management informationrequirements of the U.S. Postal Service. This net-work utilizes Mohawk magnetic tape equipment terminalswith conditioned, dedicated AT&T network facilities(201 B modems).

The systems have been very costly and have beenplagued with technical problems since their inception.An RFP was issued to industry by the U.S. PostalService on August 21, 1970, entitled Digital Com-munications System Survey. Its purpose was toanalyze and evauTate the present Postal Servicedigital communication facilities and project whatfacilities will be needed in five years. It was alsoto develop alternative systems that will prove costeffective, and recommend an integrated digital com-munication system along with a time phased plan forimplementation. The solicitation was suspended andsubsequently cancelled as a result of a GAO report.

The most significant endeavor taken by the U.S.Postal Service to take advantage of technologicaladvances in computers and telecommunications hasbeen their interest in an Electronic Mail HandlingSystem.

The objective of an electronic mail system isto take advantage of the new techniques in the fieldsof computers, data processing and transmission, auto-matic controls and communications and apply them tothe postal system. The result would be to handlemail more efficiently and to increase the productiv-ity of postal employees.

An electronic mail system processes mail inelectronic form rather than handling paper as in thepresent postal system. Instead of transporting aletter that contains hand or machine printed data,the letter contents are transformed into an electri-cal signal by means of input conversion equipment.Sorting and transportation functions are effected byswitching and transmission eluipment that direct theletter data to a destination post office. Theaddress of the letter would be :sed to select a paththrough a nationwide communications network thatwould accept the electrical data and direct it tothe destination postal facility. Output conversionequipment then prints out a replica of the originalletter onto paper that is subsequently delivered tcthe addressee.

Some mail processing functions, however, wouldgradually change to accommodate new developments,while others would be developed to handle new typesof mail. For example, computer-generated mail suchas credit card billings, nationwide advertising andmailing lists, and checks that reside on computermagnetic tapes can be transmitted over telecommuni-cation lines to sectional center facilities. Thesewould then be put into hard copy form first, andplaced in a mail system at a single central facilityas is presently done.

The goal of an EMH system is nationwide nextday delivery. However, electronic mail offers theuser other advantages, such as direct access to thesystem for immediate mail transfer. For example,where large volume mailers want timely individualdelivery, EMH could provide input conversion andhard copy output equipment with network link connec-tions directly to.the patron's facility, thus pro-viding direct access to the nationwide EMH network.

In summary, having been under various fundedcontracts with U.S. and Canada Post Offices over thepast two years the conclusions and recommendationsmade in the first Electronic Mail Handling Study arestill valid today. These are:

1. Construction of a Nationwide Electronic MailHandling System is Technically Feasible

The United States is in the midst of a dramaticphase of technical growth. The advances made inareas of data processing, transmission and controlhave been particularly significant. The purpose ofthe first five work tasks of this study was to assessthese advances and the equipment presently availableto determine if the implementation of an EMH systemis technically feasible. The result of this effortwas that in some instances present equipment is in-adequate, however, the technology does exist todevelop equipment of sufficient capability.

2.12

25

2. It Was Recommended that a System Study be Per-formed to Obtain a Cost Effective Configurationfor an EMH System.

The overall objective of the study (which iscurrently in progress) is to determine if an elec-tronic mail handling system can provide dependablemail service at a reasonable price. Before a sys-tem c.In be developed to handle mail electronically,a model of its inputs, outputs and traffic demandsis being generated. The model will provide thedata necessary to define preliminary system config-urations and equipment requirements. An analysiswill then be performed to synthesize a system thatis optimized with respect to cost. The outputs ofthe study will include:

A. The configuration of the system's collection,distribution and delivery network.

B. A hierarchy of postal collection centers.

C. The equipment required to process the mail ineach type of -enter.

3. It was Recommended that a High-Speed FacsimileEquipment be Developed Especially for ElectronicMail.

Existing facsimile equipment is too slow tohandle the anticipated electronic mail volumes.Most equipments are designed to operate at scan-ning speeds compatible with a telephone line orother common carrier channel. The wide bandwidthchannels used for electronic mail transmission willpermit faster conversion, so suitable high-speedfacsimile equipment should be developed. Aorerapid facsimile conversion can be achieved by em-ploying data compression methods to the signal out-put from the scanner. Data compression permitsbetter utilization of the transmission channel band-width so conversion times can be-reduced and there-fore result in more economical conversion.

A study into methods and application of datacompression to facsimile signals should be initi-ated. Typical facsimile scanning procedures do notpermit generation of a digital address. The addressmust be either entered separately or recognizedfrom the facsimile scan signal. At high thruputrates separate manual entry would be impracticaland automatic entry methods must be employed. Anevaluation of suitable address insertion techniquesshould be made and appropriate equipment designed.

4. A Study of Paper Handling Techniques wasRecommended.

Most mail suitable for electronic handlingwill he collected and delivered in the form ofpaper. Prior to input conversion envelopes mayhave to be opened, the letter removed, unfolded,faced and stacked. Automatic paper handling equip-ment must then feed each page to the conversionequipment and transport it through the reading areato an output stacker. The equipment may have toaccept letters that vary in thickness, size andquality. Folds, creases and tears could cause twopages to be fed at one time or result in jammingof the transport mechanism.

The tachnology of high-speed paper.handling isnot well documented; experience seems to be themost useful factor in designing equipment that willoperate reliably at high speed without jamming.

2.13

For this reason, we recommend a study to evaulatethe problems of high-speed paper handling tech-niques. The study should examine the problems ofhigh-speed paper handling and make recommendationson methods appropriate for handling electronic mail.The study should also determine whether a specialform or envelope should be used for electronic mail.

5. OpticV Character Readers are Currently notuita ie for-Eiectronic Mail Conversion.

Optical Character Recognition (OCR) equipmentspresently used in business applications have not beendesigned to read the variety of print and type stylesthat occur in letter mail. OCR's used by the PostOffice for reading addresses from letters give sat-isfactory performance but have error rates in excessof those acceptable for electronic mail corversion.Experimental readers not yet in production claim tobe capable of reading any machine-printed material.However, these readers are expensive and not consid-ered fast enough for electronic mail conversion.

6. A Special Purpose Switching System Must beDesigned to Sort, Route and Control ElcctronicMail.

The switching function is the most complex partof an EMH system. Switching equipment is used tosort, route and control the flow of electronic mail.Efficient processing will depend upon the use ofhigh speed switches, digital computers and datatransmission equipment in a nationwide network.These equipments are presently available but aswitching system must be designed to satisfy thespecial requirements of electronic mail.

7. Transmission of Electronic Mail can Be Accom-plished with Presently Available Equipment.

Advanced communication techniques presentlyemployed in data transmission by microwave radio,coaxial cable and satellite can be utilized in anelectronic mail handling system. The military andtelephone transmission capabilities are examples ofsystems that feature bandwidths compatible with esti-mated electronic mail needs. Moreover, the datahandling capacity of transmission facilities promisesto increase at a faster rate than the predictedelectronic mail volume.

8. Privacy of the Mail During Transmission isVirtually Assured by the Technical Complexityof Transmission Methods.

The sanctity of the United States mails ispresently ma;ntained by tradition and postal laws.The mark of an uncompromised letter is an unopenedenvelope. An electronic mail handling system hasno such symbol of security. However, mail in elec-tronic form will offer a privacy safeguard withoutregard to honesty or personal integrity. The reasonis that the complex modulation techniques used intransmission facilities requires that a potentialintruder possess considerable technical capability.In addition, the cost of the equipment necessary tointrude on these advanced systems is beyond themeans of most individuals.

References

1. Ravenis, J.V.J., "Properties of Mail ProcessingEpochs in Postal Systems," presented at 38thSession of the International Statistical Insti-tute, Wash., D. C., August 10-20, 1971.

26

2. "A Study of Electronic Handling of Mail,"General Dynamics Corporation, Report No.R-69-046-1 through 9, U. S. Postal ServiceContract No. RCR 30-70, Volume I-IX.

3. 'Digital Communication System," U.S. Post OfficeDepartment, Bureau of ReSearch and Engineering,RFP 54-71, August 21, 1970.

2.14

27

COMPUTER TO COMPUTER COMMUNICATIONS

VIA SATELLITE DATA LINK

H. A. BUSTAMANTE

PHILOO FORD WDL3939 Fabian Way

Palo Alto, Calif. 94303Tel. 415-326-4350

Digital data communications at ever increasing rates

are being used to convey all forms of information.

For years this technique has been used in telemetry

systems for gathering information on the status of

rockets during launch and in flight to their target,

on earth-boUnd satellites manned and unmanned, on deep

space satellites and for uncounted other uses.

The use of digital computers to solve a eemingly end-

less variety of problems, has similarly enjoyed a tre-

mendous diversification and growth. In order to func-

tion usefully, a computer system must be given infor-

mation upon which it can operate to develop the des-

ired output. This computer input normally takes the

form of paper tape, punched cards, magnetic tape data

or some other digital data form. Even in those cases

where the data exists in some analog form, the first

operation performed on the signal is to digitize it

thereby converting it into a form acceptable to the

computer.

Noting the proven and accepted use of both digital com-

puters and digital data links, it is not surprising that

their joint use should be considered. This is especially

true when nc.:zrzl large, mutually remote, computer facil-

ities have need to exchange large quantities of data. The

need and advantages of high-rate digital communications

between computers can be easily demonstrated. A stand-

ard 14" tape reel operating with seven tracks and a bit

packing density of 800 bpi contains approximately 109

bits of binary data. There are two ways of getting this

data from one user facility L. another: the tape reel

can be hand carried (physically transported) or the data

can be transmitted via a communication link. In recent

times, transmitting data at high rates has been taken

mean transmittingat 2400 bps. Operating at this rate,

transmission of a single complete reel of tape requires

one hundred hours of continuous transmission time: If

communication could be established at 50 Kbps or 1.8 Mbps

this transmission time could be reduced to one hour and

to three minutes respectively. Communication system

eqipment able to provide computer to computer data

transfer at these rates has been developed by Philco-

2.15

Ford Western Developement Laboratories and is the subject

of this paper.

The Tverall operation to be performed is to read a

magnetic tape, transmit it and reproduce it at the

receiving facility in its exact original form. Decep-

tively simple though it sounds, threc separate data

processing problems must be solved to successfully

develop such a communication system. First the en-

tire tape data and foImat must be converted to a form

recognizable by the receiving equipment so that it

can regenerate the original tape. Secondly, the com-

puter appears to the outside world to be an asynchron-

ous, 16-bit parallel data source. Digital communica-

tion systems must be synchronous to maximize communi-

cations efficiency and, furthermore, generally require

a serial data source. Finally, the data to be trans-

mitted must be received error free. All communica-

tion links make errors. The goal of this system

was to achieve a bit error rate (Pb) of no more than,

one error in 1010 transmitted data bits, i.e. Pb

5

-1010 .

The equipment developed by Philco-Ford WDL utilized

Honeywell 516 computers operating with Honeywell tape

machines. A special-purpose Interface Unit and high

efficiency triple-error-correctiag Threshold Decoder

developed by Philco-Ford provide: (a) the asynchron-

ous to synchronous conversion, (b) parallel to serial

conversion, (c) the data formatting and (d) the high

efficiency, law-error-rate operation of the link.

Another very important feature provided,which can

only be fully appreciated when working with an oper-

ating system,is a very efficient and easy to use soft-

wate system. Efficiency is measured here in terms of

data processing speed and of maximum simplicity in

terms of demands placed'on operator educational require-

ments. To complete the communication system Philco-

Ford WDL has off-the-shelf data mOdems capable of

operating within 0.5 dB of theoretical biphase-shift

keyed (BPSK) performance. Use of a Philco-Ford BPSK

modem, together with the other above described equip-

ments, a complete computer-to-computer high rate link

can be implemented. Typical performance character-

istics for the system are presented in Table 1 assum-

ing the use of a 40 ft. ground terminal and operating

through an IDCSP satellite (1).

A system similar to this has been implemented by

Philco-Ford WDL and was previously described in the

literature (2). The realization of this system must

not be looked upon as a special, one-of-a-kind, type

28

of situation. The need for computer-to-computer commun-

ications is growing and will become, in the near future,

an ever-growing need clamoring loudly to be satisfied.

The advantage of satisfying this need via a satellite

communication link is not only that it performs the task

well but more economically than other available means,

e.g. ground based common carrier.

References

(I)

TABLE 1

PERFORMANCE CHARACTERISTICS OF A TYPICAL COMPUTER-TO-COMPUTER LINK OPERATING

THROUGH A 40 FT EARTH TERMINAL AND IDCSP SATELLITE

DATA RATE - Kbps

BIT ERROR PROBABILITYC/kT > 67 dB (Hz)

2400 FT REEL TRANSFERTIME (MINUTES)

556 bpi, 36 ips

800 bpi, 80 ips

800 bpi, 150 ips

<

50

10-15

41.0

55.8

55.8

<

56.25

10-15

36.6

49.7

49.7

<

112.5

-1510

18.2

24.8

24.8

225

10-14

13.3

12.4

12.4

450

3 x 10

13.3

6.4

6.4

-10

CO

13.3

6.0

3.2

R. S. Davies., "A Description of Communication

Satellites Developed for the Department of

Defense", Proceedings of AIAA Unmanned Space-

craft Meeting, Los Angeles, Calif; March 1965

(2) D. L. LaBanca, G. R. Ash, J. J. Spilker, Jr,

"Computer-to-Computer Satellite Communicationo",

EASCON '70 Convention Record pg. 252-259.

2.16

, 29

TRANSMISSION CONSIDERATIONS BETWEDT SWITCHED SERVICE-AND PRIVATE LINE DATA COMMUrICATIONS

R. D. Hailey - Pacific Telephone Company, 408-291-4463F. E. Ward - Pacific Telephone Company, 408-292-4077

111 North Market Street, Room 612San Jose, CA 95113

INTRODUCTION: The purpose of this presentation is to pro-vide designers and users of data communications servicewith an understanding of the two basic telephone communi-cations services, the DDD Network and Private Line.

The DDD Network provides the electrical transportation ofcustomers' messages from one location to another. Switch-ing includes identifying and connecting independent trans-mission links to form a continuous path from one terminalto another.

The simplest connection involves voice frequency trans-mission between two stations through a single switchingoffice. More complicated connections may involve manylinks in tandem and include several switching offices.

Tly, Transmission paths in the network may be divided intotwo categories, station loops and trunks. The stationloop is normally a voice frequency facility using a tele-phone cable pair and is dedicated to the use of an indi-vidual station. The loop provides a two-way path betweenthe customer's terminal equipment and the local centraloffice. The loop is usually the largest single invest-ment directly associated with a particular station. Eco-noxical loop design is thus of primal importance. Whileloops are dedicated to an individual uustomer, trunks areshared by many customers and provide transmission linksbetween switching offices.

SUBSCRIBER LOOP AND TRUNK CONSIDERATIONS: The optimum de-sign of the local loop is of considerable importance. TWoloops are a part of every telephone connection so theirelectrical performance can have a strong influence on thetransmission quality of the service we provide. The selec-tion of wire sizes and loop lengths is based on loop re-sistance and a set of rules which take into account thecorrelation between resistance and attenuation.

Rules Affecting Loop Design:a. Select the most economical (smallest) gauge, or

combination of consecutive gauges, pezmitted bythe conductor resiStance range of the centraloffice.

b. Provide loading on all loops longer than 18 kilo-feet. From the standpoint of transmission and eco-nomic design, the H88 loading system is usually themost attractive.

c. Limit cable bridge tap to 6000 feet.

Very long suburban loops present a special problem. Meet-ing the office resistance range at the end station may re-quire considerable coarse gauge cable. -An economic balancemust be struck between a cheaper high resistance loop andthe expense of extending the office range.

The impedance of a:local loop terminated by a telephone setvaries as a function of frequency, cable design, and looplength. Theoretically, these impedances could be adjustedby the inclusion of suitably designed networks, but this iseconomically unattractive because each loop would have tobe so treated. Individual loops, which may have differentimpedances, are connected by end-office to trunk facil-ities, which may also have different impedances. However,there are fewer trunks and their costs are shared by manycustomers. Control of trunk impedanCe is therefore moreeconomical; precision networks and impedance compensatingnetworks of various designs are provided for this purpose.

3.1

Intertoll trunks are designed to provide good impedancematches at their terminals and at intermediate points.Furthermore, intertoll trunks generally introduce rnpreciable freq-,ency distortion. Thus the atten-uation of an intertoll trunk usually determines its contri-bution to the effective loss of a circuit. In the exchangeplant, loops and trunks are normally electr!..cally shortand, as mentioned earlier, do not have particularly goodimpedances at junctions. Thus, the impedance at a par-ticular point of a built-up connection will depend on theimpedancs terminations at remote points. Likewise, thepower loss will be a function of the attenuation of thecomponents and the reflection gains and losses at thenumerous junctions.

NETWORK: The telephone systems in the United States andCanada handle more than fifteen million long distancemessages a day. Thes . are routed over a ,.:omprehensive net-work of more than 300,000 long-haul trunks which intercon-nect about 1,600 long distance switching offices. Thisnetwork serves, with few exceptions, all of the tel.phonesin these two countries and provides for establishing con-nections to most other parts of the world.

Large volumes of traffic between any two points are gen-erally routed most economically over direct trunks. Whenthe volume of traffic bAween two offices is small, how-ever, the use of direct trunks is usually not economical.In these cases the traffic is handled by connecting to-gether, by means of switching equipment at intermediateoffices, two or more trunks to build up the required con-nection. The places where interconnections are made aregenerally known as "switching centers". "Nilt-up" con-nections may involve several switching centers if theoriginating and terminating locations are a great distanceapart. It is important that telephone plant be, designedto provide a constant quality of transmission and servicefor this multiswitch traffic as well as the large volumesof traffic handled by the less complex direct and singleswitch connections.

The needs of distance dialing are met by switching andtrunking arrangements that employ hierarchical routingdiscipline and the principle of Automatic Alternqte Rout-ing to provide rapid and accurate connections, while makingefficient use of the telephone plant. The hierarchtcalrouting discipline provides for the collection and distri-bution of traffic, and permits complete interconnectabilityof all offices. With the Automatic Alternate Routing prin-ciple, a call which.encounters an "all trunks busy" cone.-tion on the first route tested is automatically "routeadvanced" and offered in sequence to one or more alternateroutes for completion.

Under the Switching Plan each office involved in the com-pletion of long distance calls is classified and desig-nated according to its switching function, its inter-relationship with other switching offices, and its trans-mission requirements. The class designations given to theswitching centers in th network determine the routingpattern. Figure 3 illustrates how various classes ofoffices might be grouped. The office classifications,their functions, and the switching areas they serve aredescribed in the following paragraphs.

The central office equipment entities where telephoneloops are terminated for purposes of interconnection toeach other are called "End Offices" and are designated as"Class 5" offices.

The switching centers which provide the first stage ofconcentration for inter.toll traffic from end offices are

Toll Centers or Toll Points and are designated as"Class 4". Certain switChing centers, in addition to con-necting end offices to the network, are selected to serve

30

as higher ranking switching centers. These are PrimaryCenters, designated "Class 3"; Sectional Centers, desig-nated "Class 2"; and Regional Centers, designated"Class 1". Collectively, the Class 1, 2 and 3 officesconstitute the Control Switching Points of the distancedialing network. Each separate switching unit must beassigned its own classification within the hierarchicalrouting plan.

It is not necessary that Clrss 5, 4 and 3 offices mustalways home on the next higher ranking (lower classnumber) office. For example, Class 5 offices' may beserved directly from any higher ranking office, Fig. 3.Direct high usage trunks are provided between offices ofany class wherever the volume of traffic and economicswarrant the necessity. High usage trunk groups carrymost but not all the offered traffic in the busy hour.Overflow traffic is offered to an alternate route.

There are four simple rules that govern the routing of acall, see Fig. 3: (1) Never use more than two chains.(2) Never gO WO a foreign chain. (3) Never go down thelocal chain. (h) Always take the shortest availableroute. It should be noted that the maximum number oftrunks connected in the final route chains from Class 4office to Class 4 office cannot exceed seven for intra-country calls or eight for a very few United States-Canada calls. These plus the trunk to the Class 5 officeat each end, result in a maximum of 9 trunks in tandem forintracountry calls and occasionally 10 for United States-Canada calls. The probability of a call traversing allpossible trunks of the final routing chains is estimatedto be only a few calls out of millions. Calls betweenhigh volume points are completed on direct trunks regard-less of distance; relatively few encounter multipleswitches. As traffic growth occurs, a relatively largerportion of the traffic is carried on direct routes.Multiple switching is the rule, however, between in-frequently called locations.

ALTERNATE ROUTING: The successful completion of long dis-tance traffic depends upon a high-speed trunk network sothat "all trunks busy" conditions are rarely encountered.Alternate routing is one of the techniques that makes thispossible with reasonable trunk efficiency. A call enter-ing the network is always routed over the most direct avail-able trunk. When the first choice high usage trunk groupis busy, a call will be alternate routed to other trunkgroups. In the example shown in Figure 3 there are 13possible routes for a calI from Station A to Station B.Only when all high usage trunk groups are busy will a callbe routed over the final trunk route.

VIA NET LOSS CONCEPTS:

Design Factors: The following transmission considerationsare Important in determining the lowest practicable lossesat which trunks may be operated:

a. Echob. Tolerance to Echoc. Singing

Echo: Echo is the sum of all the transmitted energy whichhas been reflected back to its source. Fig. 1 shows howan echo arises on a telephone connection. This figureshows the relatively simple case of a 4-wire trunk connectedby means of 4-wire terminating sets to a 2-wire terminationthrough the switches at each end. The 2-wire terminationsmay be anything from nearby telephone sets to sets on a widevariety of customer loop lengths on loaded or non-loadedfacilities, or on' carrier systems. There may also be inter-vening trunks on eable (either loaded or non-loaded) or onaarrier systems. The range of impedance presented by theseterminations varies widely, being different for each con-nection. The best that can be done under such circumstancesin selecting a balancing network for a 4-wire terminatingset is to choose one which is the best compromise for the

3.2

range of conditions encountared. This is known as a c-m-

promise network. It consists of a resistor and capacitorin series whose values are determined by the general 1,,velof impee...nce of the particular office. Understandably,the balance in any given connection might not be ideal.

When the customer at Point A talks, his speech energy(the heavy solid line) travels along the circuit to PointB and on to the distant customer. However, because ofthe impedance mismatch between the local plant and thecompromise network at Point B, some of this energy (thedash-dot line) is reflected back across the 4-wire termi-nating set and is transmitted back to the talker's re-ceiver. Thus he hears his own voice and, if the time re-quired for his speech to travel to Point B and back islong el:ough, the returned energy appears as a distinctecho; hence, the term "talker echo". The round trip delay(usually expressed in milliseconds) is the time it takesthe energy from the speaker's voice waves to travel tothe distant end of the circuit and back again. Both themagnitude and delay of the energy affect the tolerancelevel of the echo. The greater the delay, the less echolevel the talker can tolerate.

At Point A, the same kind of impedance is present as atPoint B. Consequently, some of the talker echo arrivingat Point A is again reflected back across the 4-wireterminating set at that point and is transmitted back (thedotted line) to the subscriber at Point B. This is knownas "listener echo". However, the extra loss across the4-wire terminating set at Point A and the added loss en-countered in the additional trip down the circuit soattenuates the listener echo that it is usually not con-trolling in this type of connection. For data trans-mission talker echo has no effect on the data transmitter,but listener echo can be extremely detrimental to the datareceiver if the echo level is high enough and the delaylong enough.

The echo characteristic of a connection as discussedabove imposes a lower limit on the loss at which a trunkcan be operated. Thus it is the trunk loss itself towhich we must look to control echo. The performance ob-jective for talker echo (customer to customer) is asfellows: The design of trunks should be such that talkerecho will be satisfactorily, low on more than 99 percentof all telephone connections which encounter the maximumdelay likely to be experienced.

Singing: Referring to Fig. 1 again, it can be seen thatif the current returned to Point B by the "listener echo"path is greater than the original current arriving atthat point, a condition is set up which sustains a cir-culating current around the loop consisting of the twosides of the circuits and the terminating sets at the ends.This condition can arise at any frequency due to low re-turn losses at Points A and B and higher gains in linerepeaters or carrier channels. Stated in another way,singing occurs when, at any one frequency, the sum of allthe gains in the transmission paths exceeds the sum ofall losses. Singing can be prevented by limiting re-peater and carrier system gains and, preferably, by im-proving the terminal return losses.

VIA NET LOSS (VNL) DESIGN: It is desirable to asign theoverall loss so that each trunk of a connection operatesat the.lowest possible loss consistent with echo and sing-ing requirements. This is accomplished through the useof echo suppressors and VNL design. The VNL design plan

was arrived at by first considering the tolerance ofcustomers to talker echo, then taking into account thestatistical variations of the elements involved, and fromthis determining the loss required between end offices inan overall connection. Loss per trunk requirements areobtained by allocating this averall connection loss amongthe number of trunks in the connection.

Figure 2 shows the design loss to satisfy echo and singingrequirements as a function of the number of trunks to beconnected in tandem and the round trip delay of the facil--Aes. Inspection of this figure reveals that as thenumber of trunks is increased, an increase in loss ofapproximately 0.4 dB per additional trunk is required.This increment compensates for the increased loss vari-ability with an increased number of trunks. The minimumloss of 4 dB is required to prevent a singing condition atlow time delays. Most long-haul carrier systems have apropagation time of about 0.007 milliseconds per mile. To

estimate the round trip delay of a connection the propaga-tion .%ime should be multiplied by twice the one-way con-nection length.

Via net loss design rules are only used when the round tripdelay is less than 45 milliseconds. This is done to limitthe maximum trunk losses so that the nominal received poweris adequate. When the round trip delay exceeds 45 ms, atrunk is equipped with an echo suppressor and operated atzero loss. Fig. 3 shows the objective losses for trunksin the switching plan. These objectives provide a satis-factory compromise between: (1) the need for sufficientlylow loss to provide natural received volumes and minimumcontrast in received volumes on different calls, and(2) the need for sufficiently high losses to ensure ade-quate performance from the standpoint of talker echo andnear singing. These are the objectives obtained by Via NetLoss (VNL) design considerations.

PRIVATE LINE SERVICE: An alternate mode of operation fromthe DDD network is Private Line. Although the facilitiesused to provide the data channels are the same as thosefound in the DDD, control with regard to choice of facilityand routing is available to the telephone company designengineer. Because the choice of route and facilities eanbe predetermined, so can the overall transmission charac-teristics. Appropriate equalization is administered asrequired. The user states, at the time of placing his order,the parameters he desires. The worst case condition withregard to overall circuit characteristics can be found inthe Bell System technical reference manual entitied "Trans-mission Specifications for Voice Grade Private Iine DataChannels".

Should the data user desire, the Private Line data servicescan be ordered with certain limitations, on a two point,multipoint, or switched basis. The limitations are basedupon the degree of equalization required and the number ofpoints involved.

DATA SERVICE PLANNING: Data service planning involves theevaluation of specific user requirements and the considera-tion of many alternatives. Several areas of paramount con-cern in planning a data system are: volume of data, urgencyof data, sensitivity to errors and the ability to handleinterruptions. As these areas are fundamental to the datacommunications process they should be thoroughly evaluatedprior to conaL...ering any specific implementation. Once thisis done, attention can be directed toward finding a serviceor combination of services that fulfill the system require-ments.

The switched nctwork offers the data communications userconsiderable flexibility in terms of the widespread avail-ability of connections and economical rates. Its limita-tions include the variability of performance from call tocall, limitations on speed imposed by the voice bandwidthnature of the network and the time required to set up con-nections. Where these limitations are serious, it may bethat other services are better suited to fulfilling specificrequirements. These services include switched and non-switched voice grade private line services, several typesof teletypewriter oriented data services and wide band dataservice. In planning a total data system, these other ser-vices should be considered as alternatives, depending ontraffic and feature requirements, or they may be used incombination with switched network service.

Whether the data user elects to utilize Private Line orthe DDD network for his communication link, it must berealized that the facilities involved introduce distor-tions. The term "window" has been used to describe thetransmission medium. It may be a window indeed, but itis not without imperfections. It contains delay, bothabsolute and envelope, loss, non-linear loss vs freouency,white noise, and impulse noise, as well as possible phasejitter, frequency off set and occasional hits due to micro-wave switching.

ECHO PATHS

1

I L--TS?YIRE TERMINATING ETC, C>

1

tiTo

SWITCHESTSEERTIAtl_i_

N BALANCING 17--- TARP'TO

NETWORK SWITCHES

POINT A FOINT BTALKER'S SPEECH PATH

.-- TALKER ECHO PATHLISTENER ECHO PATH

FIG. I

RELATIONSHIP ETWEEN OV LLLLL CONNECTION LOSS AND ECHO PATH DELAY(CLASS 5 TO CLASS 5 OFFICE /

CLASS IREINIONAL CENTER

CLASSSECTIONAL CENTER

CLASS 3PRIMARY CENTER

CLASS 4TOLL CENTER

CLASS 5END OFFICE

3 3 32

OVERALL CONNECT ON LOSS WHICH GIVESSATISFACTORY ECHO IN ..%0P CASESI.

16

0

smimmommvialaisummommormoumommoissumumozzosImmo ma'amEEEEEEE*EMME11.11111En3A,ANKIIIEEMPAEEEEINEffEEV2IEEEEEMENIEVMHEEEEEMEV7illffil111111%/M111111MEMIII

/1471ENIEEINEEIA a 1CATION RD4FS=Mt SUPPRESSCR

/// TA Si= TRIMMEENE ME

20 KO 60 40 100 110ROL/NO TRIP ECHO PATH DELAY-MILLISECONDS

FIG. 2

TRUNK LOSSESMNTH VIA NET LOSS (VNL) DESIGN

0.0 41 (MAX, 0.5)

A ga

z

1:; 211 I ---'444444ug,..n./

? /

13.111AX SW

VINLJ11143-2.5111

A @7I ECHO SUPPRESSOR N0YE5IZIANO(5)----. HIONUEADE

FIG. 3

Cost Effectiveness Evaluation ofConcentrators in Data Communications

Networks

Norman F. Schneidewind

Department of Operations Researchand Administrative SciencesU. S. Naval Postgraduate SchoolMonterey, California 93940

(408) 646-2719 or 2041

The Problem

Concentrators are employed in datacommunications networks for the primarypurpose of reducing line charges in long-line networks. This advantage must beweighed against the increased thruput andlower terminal response time provided bythe more expensive point-to-point network.Concentrators perform the function of multi-plexing multiple input lines onto one ormore higher speed output lines. In addition,concentrators provide capabilities for mess-age assembly, code conversion, editing,formatting and bufferring. Concentratorsmay be either hard-wired or programmable.Hard-wired concentrators have fixed sampletime, number of samples, number of lines,input rate, message size, etc., while pro-grammable concentrators are frequently minicomputers in which the above parameters canbe varied to a considerable extent. Inaddition, programmable concentrators canperform message accounting, traffic analysis,billing, dynamic buffer allocation, prioritymessage processing and elaborate error con-trol routines. Thus, programmable concen-trators provide greater application flexi-bility but at higher hardware and softwarecosts.

Techniques are needed for determiningwhether lines should be concentrated orrouted on a point-to-point basis in a net-work in which user terminals are to be con-nected to a computer. Secondly, if lineconcentration is appropriate, it is neces-sary to choose between hard-wired and pro-grammable concentrators. Both effective-ness and cost factors must be considered inthis evaluation. From Ole point of view ofthe user at the terminal, response time isthe most important quantitative performancemeasure. From a total network performancepoint of view, thruput is the most appro-priate measure. Cost factors include thefollowing for each of three network connec-tion schemes:

Pointto

PointModems.Point to pointline charges x.Installation x.Concentrator(s).Input line(s)Output line(s)charges.Software development

In this evaluation, the costs of termi-nals, transmission controller or front-end

Hard-Wired ProgrammableConcentrator Concentrator

3.4

processor, and central computer are approxi-mately the same for point-to-point and con-centrator networks.

Approach

The approach which is employed is todevelop queueing models of selected networksand to compare the effectiveness and costsof using concentrators with a point-to-pointconnection. The analysis consists of thefollowing four phases:

1. Develop feasible networks for both concen-trator and point to point networks.

2. Compute terminal response time and networkthruput for the two types of networks.

3. Compute the total cost of the two typesof networks.

Z. Compare the effectiveness and costs ofpoint-to-point with concentrated networksand determine which of the following ismost appropriate:

- point to-point connection- hard-wired concentrator- programmable concentrator

Phase 1 considers feasibility from twostandpoints. One purpose is to develop net-works in which the traffic intensities andqueues in each part of the network are notexcessive. The second purpose is to providea network which satisfies response time andthruput requirements for specified number ofterminals and input rates.

Next, (Phase 2), terminal response timesand thruput rates are computed for each con-figuration and for various input rates. Inthe case of programmable concentrators, theeffects on performance of factors such aspriority message processing and buffer stor-age areas are evaluated. In Phase 3, feas-ible network toted costs are computed for thealternate networks, considering the costfactors previously listed. Finally, inPhase 4, incremental response times and thru-put rates are compared with incremental costsin order to select the most appropriate con-figuration. Curves of effectiveneas versuscost for the three alternatives are pre-sented.

Conclusions

When the number of user terminals canbe varied nor a fixed message input rate,the point-to-point network will usually besuperior to the concentrator network on botha cost and effectiveness basis, except whenthe line runs are extremely long. Thisresult is due to fewer terminals and linesbeing required for the point-L,)-point net-work for a given level of effectiveness orcost. In the case of a concentrator network,the additional processing time introduced bythe concentrator(s) requires the inputtraffic to be distributed over a larger num-ber of terminals and lines in order toachieve a given system response time or thru-put. This results in higher cost for givenlevels of effectiveness or, alternately,lower effectiveness for a given cost. Theconcentrator network is particularly at adisadvantage when low response time,

33

high thruput or low mileage line runs char-acterize the network. These results do nothold as the length of the network becomeslarge, beCause line charges will eventuallydominate cost considerations and the point-to-point n,-...,twork becomes excessively costly.

A different situation pertains when afixed number of user terminals must be em-ployed, due to a geographic or organizationalrequirement for terminals. In this case, theeconomies of less equipment cannot beachieved in the point-to-point network. Inthis case, the point-to-point network willalways provide shorter response time andhigher thruput; however, cost will be higher.The following are the characteristics of thefixed terminal case for a given input rate:

network cost rises faster in point-to-point networks as the number of terminalsrequired increasesnetwork cost is significantly increased asline runs increase in point-to-point net-worksnetwork cost increases negligibly in con-centrator networks as line mileageincreasesdifferences in response time between thetwo networks decrease with an increase inthe required number of terminalsdifferences in thruput between the twonetworks increase with an increase in thenumber of required terminals.

These characteristics-Signify that theconcentrator network has an advantage whenthe number of required terminals is large,line runs are long and response time is moreimportant than thruput. Conversely, point-to-point networks have an advantage when thenumber of required terminals is small andline runs are short. Selection of networktype depends on the relative difference incost between point-to-point and concentratornetworks versus the relative difference ineffectiveness, for a given number of termi-nals and line mileage.

In summary, there is an important dif-ference in relative network performance andcost depending on whether the number of ter-minals is fixed or can be varied in thenetwork design.

References

Burner, H. B., et al, "The Use of a SmallComputer as a Terminal Controller for a LargeComputing System," AFIPS Conference Proceed-ings, VoI. 34, 1969, pp. 775-776.

Kaplan, S. J., "The Advancing CommunicationsTechnology and Computer CommunicationsSystems," AFIPS Conference Proceedings,Vol. 32, 179768, 1T. 119-134.

Martin, James, "Design of Real-Time ComputerSystems," Prentice-Hall, 1967, pp. 278-292and pp. 511-535.

Martia, James, "Telecommunications and theComputer," Prentice-Hall, 19691 PP. 276-291.

Martin, James, "Teleprocessing NetWork Organ-ization," Preotice-Hall,:1970, PP. 184-210.

Newport, C. B., "Small Computers in Data Net-works," AFIPS Conference Proceedings,Vol. 34, 1969, pp. 773-774.

3 :5

Stimler, Saul, "Real-Time Data-ProcessingSystems, Mc Graw-Hill, 1969, pp. 110-139.

3 4

DROPOUTS AND PHASE-HIT EFFECTS EN DATA CHANNELS

L. A. Sibley

Pacific TelephoneRoom 606, Ill N. Market StreetSan Jose, California 95113

(408) 291-4556

Data communication channels extending over more thah avery few miles are subject to "dropout" and "phase-hit"effects which Introduce error bursts. The dropoutphenomenon is the more serious of the two, and is re-sponsible for the most severe error occurrences. All

long-haul, and most short-haul, communications mediaexhibit these effects to some degree. Advanced sys-tems nom coming into prominence, for example all-digi-tal networks, will relieve but not eliminate the pro,blem.

Dropouts, or brief signal interruptions lasting perhapsone to 1000 ms, result from a variety of causes. Pro-tection switching on microwave radio, either automaticor manual, causes momentary losses of signal. The ef-ficient one-for-five protection systems used for long-haul service involve longer switching times than thesimpler one-for-one arrangements used in short-haul ap-plications. Troposcatter systems are subject to brief,deep fades which effectively block the data signal.The occurrence of fades on all radio systems, line-of-sight particularly, depends on seasonal and diurnal ef-fects. Hence the dropout rate can be expected tochanoe with time. The quality of radio maintenance, byaffecting the tolerable fade depth, has its influenceon the dropout rate. PCM carrier systems occasionallylose framing, resulting in brief stone! losses. Pro-tection switching on coaxial cables results in the sameefrect. Maintenance and patching activities on any sys-tem induce dropouts, as can equipment defects. The ageof the equipment design naturally affects its toleranceto such effects power transients.

Data will be presented on ihe rate of occurrence ofdropouts on typical transmission facilities used fordata transmission at all speeds, as taken from CCITTand Burl System sources and local studies. Because thesame mechanisms affect them equally, dropoul durationsand rates of occurrence are ewpected to be Omilar onall data channels, teletype-spaed through wideband.

The rates of occurrence for dropout effects are extreme-ly varleOle from one facility to another, even on iden-tical routes. The same holds true for different direc-tions of the same data channel. The variability affectsboth the typical .duration and the number of events perunit Time.

Phase hits are an effect of secondary importance.These are sudden Jumps in the phase of a received datasignal. Principal causes are differences in lengthbetween protection-switched coaxial cables in thesame sheath, and switching of carrier supplies in FDMmultiplex. Redid systems are generally designed tominimize phase shifts during switching, but are na-turally open to any phase change In the multiplexequipment. Phase changes up to 3600 can occur andlast any amount of time. Slower changes - "phasecrawl" - also odour.

Phase-hit effects are a minor cause of trouble incomparison with dropouts. Unfortunately, most com-mercial phase-hit detectors respond also to dropOuts,since phase becomes discontinuous when a signal lossoccurs. Likewise, Impulse noise can also result Inerroneous phase-hit totals.

Phase changes of 30° or more on lono-haul channels areusually much less frequent than 30 times per hour, asan upper bound. Short-haul facilities are essentiallyfree from phase hits.

Both dropouts and phase hits result in bursts of errors.The seriousness of these impairments depends naturallyon the speed of transmission, but also on the dataorganization (character-interleaved versus bit-inter-leaved multiplex, for example) and the block length.Forward-acting error correction is frequently effectiveagainst the shorter bursts; ARQ systems are favored inthe face of long bursts. The interval between burstsis also important. Directly-multiolexed data systemswith no protection means are extremely susceptible tothese effects. Speed of sync recovery in data setsand multiplexers is of obvious importance, as is thelength of the signal loss required to cause an auto-matically-equalized data set to retrain. Data multi-plexers operating back-to-back between differenttransmission channels without trouble monitors or othermeans of sectionalizing error bursts are both extremelysusceptible to sync loss and virtually impossible totroubleshoot. The makoup of the circuit has its owneffect on the burst rate; most long circuits are com-posed of both short- and long-haul facilities in tandem,and a great many long-haul channels are comprised ofboth radio and cable sections. In addition, the rela-tive amounts of coaxial cable and radio in a particularlong-haul channel may change frequently as the comp-munications carrier's ,rowth program progresses.

3.6

Dropouts and phase hits are a routine occurrence ondata communication channels. A successful systemdesign must include safeguards against the error burststhat they cause.

3 5

THE RJE ENVIRONMENT:

HIGH-SPEED VOICE GRADE COMMUNICATIONS

By: Robert Larribeau, Jr.Vice President-Operations

Information Systems Design, Inc.7817 Oakport Street

Oakland, California 94621(415) 562-4204

While a great deal of attention has been paidto the development of timesharing systemsover the last several years, remote batchsystems have developed as a practical methodfor using computers. Remote Job Entry (RJE)systems provide access to a batch orientedprocessing system such as the CDC 6600, theIBM 360/65, or the UNIVAC 1108 through ahigh throughput oriented terminal. Theoperating systems on these computers providethe remote user with all the capabilitiesavailable to the on site user; as a matterof fact, at ISD the service provided theterminal user is better than the serviceprovided to the in-house user.

The typical remote batch terminal consistsof a 300 card per minute reader and a 300line per minute printer and costs about$1,000 per month. Terminals with bothhigher and lower speed peripherals areavailable. The throughput of these termi-nals are determined by line speed as much asperipheral speed. Peripherals such as tapedrives and plotters are available but areseldom used.

Communications facilities range from dial-upto wide band systems. A dial up facilitywith 2000 bits per second (bps) data setswith their 150 millisecond turnaround timeprovides an average throughput that rangesfrom 80 to 150 lineS per minute. Four wireleased lines provide from 200 lines per min-ute at 2400 bps to 700 lines per minute ormore at 9600 bps. A four wire leased line toany two points in the Bay Area costs about$150 per month. Modems cost from $75 permonth for 2400 bps modems to $380 per monthfor 9600 bps modems. A terminal with 300lines or cards per minute capability, a 2400bps modem, and a leased line would cost about$1,500 per month.

The communications schemes used in the RJEenvironment have two prime goals, one iserror control, and the other is the maxi-mization of effective throughput.

Synchronous transmission facilities areused with the RJE terminal. This meansthat a message of several hundred to a fewthousand bits are transmitted in a block.The block is preceded by a sequence of aunique character called the SYNCH or syn-chronization character in order to differ-entiate between a true message and noise.If none of the SYNCH characters are re-cognized the entire message is treatedas noise and dropped.

The nominal line error rrte of one in 10 5

means that on the averagc every full pagewill contain one error. ihis error rate

3.7

is far too great considering that a typicaljob produces 30 to 50 pages of output. Eachblock has check bits to determine whether biterrors have been made in the block. If theblock has been transmitted correctly, anacknowledgement message (ACK) is sent backto the originator of the message to signifya correct transmission and that it is timeto send the next message. If the block hasnot been correctly transmitted, a negativeacknowledgement (NAK) is sent back to signifythat the previous message should be retrans-mitted. Messages may also contain a sequencenumber so that a block that is dropped com-pletely will be detected. Time-outs are alsoused to keep the terminal and the central com-puter coordinated.

Because of the 150 ms turnaround time on dialup, it is important to use large blocKs.Throughput using 300 character blocks is twicethat using 80 character blocks. However, thelonger the block, the higher the probabilityof a transmission error occuring and the higherthe cost of a retransmission. On a four wirefull duplex line where there is no turnaroundtime, the effect of blocking is not large.

A second technique that is used is to increasethe information content of each b.t. This isdone by the use of data compression techniques.The simplest of these is to truncate the recordafter the last nonblank character. Another isto use tab stops to truncate after the lastnonblank character within a group of charactersexactly like the way that the tab key on a type-writer works. A more sophisticated scheme isto replace multiple instances of a characterwith a count together with the character thatis to be replicated.

The communications system is debugged primarilyby using a test set which sends random bitpatterns over a looped back line and checksthem when they return. The test set has abit error counter which can be used to checkerror frequency on the line. It can also beused to locate modem problems.

The main problem with maintaining the system isfault location. A problem may exist in termi-nal hardware, terminal software, modems, line,central site hardware, and last, but certainlynot least, central site software. Reliablefault location is especially important sincedebugging individual components in the systemcan be quite difficult and time consuming.

The complexity of maintaining a high level ofservice in a synchronous communications networkof more than a few lines requires a high levelof technical capability today. It is necessaryto control software, hardware, and communica-tions facilities. However, major changes willcome about in the last half of this decade withthe advent of all digital networks from bothBell and independent suppliers. Modems will nolonger be necessary. The reliability of datatransmission will be much higher than it istoday, and the people maintaining the communi-cations facilities will be better equipped todebug the system. The cost of these servicesshould go down and new services will be madeavailable. The all digital network coupledwith better control of the software will makeRJE a commonly used method to distribute com-puting power.

36

"Communications in a Time-Sharing Network"D. E. CarrigerThe Service Bureau Corporation111 W. St. John StreetSan Jose, CA 95113286-9100, ext. 425

The typical time-sharing service provides its customers

access to a computer through a terminal located on the cus-

tomers' premises. The terminal communicates with the

computer through the appropriate modems and the DDD net-

work. A customer time-shares the computer with other

customers. This is accomplished, in the computer, by

alternating the work from one task to another. Thus, the

total operating time available is divided among several cus-

tomers. Time-sharing systems are designed so that each

customer seems to have the computer dedicated to his tasks.

The design of a time-sharing network must be consistent

with the design of the time-sharing service(s) that will use it.

The factors that must be considered are:

1) Response: The customers' most readily accessible

measurement of a particular time-sharing system is

the response time -- the response time being the

time between the customer striking the carrier

return and the terminal receiving the first character

back from the system.

Response delays introduced by the network add to the

delays Caused at the computer. The total of these

delays must fall within the acceptable range for the

action taken, i.e. response required on entering a

line of data is faster than the response required for

a command. The design and redesign of a time-

sharing network must take into account the effects on

response experienced by the customer,

2) Reliability: The hardware and software that make up

the network must give the customer uninterrupted

access to the time-shared computer. When failure

occurs, backup procedures must quickly go into

effect to minimize the impact on the customer.

The network must provide error detection and/or

/correction capabilities consistent with the needs of

the customers. The time-sharing network must, to

some degree, compensate for errors encountered on

the voice grade lines.

3) Function: The function provided by the time-sharing

network produces revenue. The function n,,,,,Icied

by a typical network includes:

a) Customer access at some number of cities (FOB

points).

b) Simultaneous access by n customers.

c) Support of different terminal types.

d) Support of different line types.

4) Cost: The cost of the network includes hardware

and possibly software.

The Service Bureau Corporation's telecommunication

network has evolved from several small networks, each

servicing a small geographic area to one nationwide network.

The evolution progressed from networks of FX lines to a

network supported by programmable data concentrators.

This evolution is examined with respect to response, reli-

ability, function and cost.

3.8

37

"Simulation in Computer Communications"

by

Dr. Naim Abou-TalebProfessor of Electrical Engineering

San Jose State College

Since the upsurge of computers that began in the

1950's, there has been a rapid growth in data communi-

cations over the voice and wide band networks. The

rapid growth of the computer field and its appli-

cations, the use of time-shared systems and the tre-

mendous amount of data to be handled is putting an

enormous pressure on the present communicatiun net-

works.

Because of the huge amount of capital needed to

provide the facilities required, and because of the

change of the nature and the scope of the information

processed and transmitted, deep concern has developed

at high management levels on a number of issues

related to the subject of computer communications.

Some of the questions asked are: (1) Are we making

use of the newly developed technology? (2) The com-

puter and communications fields are changing fast....

is it proper to invest now or wait fc;r some break-

throughs in teohnology....are they around the corner?

(3) Could we provide the services needed now and the

ones required in the next decade or so with the tech-

nology available at present....is expansion possible

without degrading the system? (4) For good quality

service....how much does it cost" Could it be done

at less cost by better utilization of machines, lines,

manpower....etc.? (5) What are the trade-offs?

For an investment of a few billion dollars over

the next few years, we a,e expected to answer these

questions....in the best and most honest way we car.

For investment in that order, we the scientific

community have to provide the management with means

and tools to make the decisions.

Simulation, with all its varieties, is expected

to emerge as the most important tool, but unfortunately

it has been used in certain cases to push certain pro-

4.1

ducts on the unsuspecting customers by flooding them

with all kinds of tables, charts, languages, etc.

It is our duty and we have the obligation of esta-

blishing an acceptable set of rules in order that

simulation will be used to give the customer the best

for his investment.

This paper covers the development of the simu-

lation technique to its present state. Proposals are

submitted on trends which should be adopted in simu-

lating the computer communication system or any of its

components.

38

INTERACTIVE MANAGEMENT OF MINERAL RESOURCES

Practical experience with the Alaska data-base

Jacques F. Vallee and Gerald Askevold

Stanford University*

This paper reports on a series of experimentsdone by the authors using an information-orientedlanguage named DIRAC-2. The purpose of these experi-ments was to demonstrate how advanced computer storageand retrieval techniques could be applied in the Earthsciences to provide planners and researchers with aflexible information tool.

Information needs in the Earth Sciences

The information needs in the geosciences fall intothree rough categories:(1) Planners at the regional or federal level need

accurate, high-level correlations of many combina-tions of parameters.(x)

(2) Mining companies and other private operationsrequire large quantities of geological, historicaland bibliographic data on the resources of a par-ticular region, property or mining district. Thisoften includes history of past production as wellas map locatiOn, type of rock, nature of ganguematerial, and so on.

(3) Researchers in public and private institutions needthe ability to store economically the data found in.the literature and to retrieve it quickly in re-sponse to unpredictable interrogations that areoften statistical in nature.

First experiments

Our first series of experiments, covering the last

few months of 1970, centered on the use of a fully-generalized data-base system called DIRAC-1. This

system was of.interest in the present context becauseit allowed us to rapidly create and develop models forinformation structures applicable to mineral properties.

In 1971 an advanced version of DIRAC was privatelydeveloped and gave us increased performance togetherwith the ability to obtain graphs and correlationsdirectly on a video display tube.03)

The case of Alaska-The rapid development of the mineral resources of

the state of Alaska has created a situation that is

highly suited for analysis from the data structurepoint of view. Not only is information scatteredamong many specialized centers, publications, and public

or private files, but it comes with a variety of for-

mats and coding systems. We were fortunate in receiv-ing the advice and help of the U.S. Geological Survey

in defining a uniform record structure for the mining

resources in Alaska and for the literature concerning

them.

The Language

The system we are using to store and retrieve thisinformation is a very high-speed, interactive languagethat has the following features:

1) It operates in time-sharing mode on a 360/67computer. The file is stored on a random-accessdisk.

2) Search commands allow the step-by-step definitionof subsets of the main file. Selected recordscan be displayed directly at the remote terminal.

3) The full range of logical operations (inclusion,exclusion, negation) is available.

4) Subfiles can be created and saved dynamicallyunder user control.

5) Use of the system.requires no previous knowledgeof programming.

6) Correlation matrices can be computed and displayedon cathode ray tube equipment. For instance, thecorrelation between type of rock and elementsproduced can be generated with a single commandfor any given subset of the Alaska file.

7) Histograms can be created and displayed on thescope in the same manner.

The commands combine to provide a flexible decision-making tool that has not been available in this fieldbefore.

REFERENCES:

1. Vallee, J. "DIRAC: An interactive retrievallanguage with computational interface". Inform.Storage and Retrieval Journal, Vol. 6, pp. 387-399, Dec. 1970

2. Computer-based Storage and rc.rieval of Geoscienceinformation: An annotated bibliography. J.Hrustcaand C.F. Burk. August 1970. Pri 'ate communication.

3. Vallee, J. et al. "The Organization of researchdata banks." Proceedings of ASIS 1971. Denver,

November 1971.

Correspondence should be addressed to: G. Askevold,

Department of Mineral Engineerin(, Stanfoid University,

Stanford, California 943054.2

39

ABSTRACT

Coding Requirements of DigitalRemotely Controlled Systems

Salah M. YousifSacramento State College, Ph. 454-6691

Sacramento, CA. 95819

This paper is an analysis of the state ofthe art of modern coding schemes and theirphysical realization. The introduction ofdigital process computers in the fields ofsupervisory control, digital communication andremotely controlled plants and objects introduceda complexity in data transmission in communicationamong these computers and the associated datalinks. Also, large industrial systems such aschemical processes and modern power systemsinvolve several subsystems located in stationsmiles away from one another, and each subsystemis provided by a minicomputer for supervisory andcontrol purposes. The major system has one largeprocess computer located at a central station whosefunctions are mainly optimizing the total processperformance through hierarchial control, andcoordination of action among the stations mini-computers. Important data infol-,ation 'is inter-changed continuously over noisy channels in thishierarchy. Therefore, reliable means should beavailable to provide secure data interchange inorder to exert correct and accurate control actionsby th 7.. actuating devices in the remote stationsand to avoid receiving erroneous information at thecentral station. The main objective in computercommunication is.high data transmission rate withsmall probability of error. Shannon's channelcapacity theorem puts an upper bound on data

. transmission rate for optimal error minimizationand shows the existence of coding schemes thatminimize the probability of decoding error. Thispaper will review and analyze coding schemes thatare capable of detecting and correcting burst errorsof finite length and methods of physical realizationof these codes. Special emphasis will be devotedto polynomial codes and Bose-Chaudhuri-Hocquenghem(BCH) Codes. Since these codes are defined overbinary Galois field GF (2m), a survey of the theoryof Galois field will be given in the paper. Linearsequential circuitry methods will be utilized toimplement these codes, and the problems associatedwith implementation of long code words will betreated.

4.3

REFERENCES

1. Ash, Robert B., Information Theory, NewYork, Wiley 1965.

2. Bartlett, K. A., "Transmission Control ina Local Data Network," Proceedings of IFIPCongress, Vol. 2, pp. 704-708, 1969.

3. Berlekamp, E. R., Algebraic Coding Theory,New York, McGraw-Hill, 1968.

4. Birkhoff, Garret and Bartee, Thomas C.,Modern Applied Algebra, New York, McGraw-Hill,1970.

5. Bose, R. C., and Ray-Chaudhuri, D, K., "OnClass of Error Correcting Binary Group Codes,"Information and Control, Vol. 3, pp. 68-79,1960.

6. Gill, Arthur, Linear Sequential Circuits,New York, McGraw-Hill, 1966.

7. Liccardo, M. A., "Polynomial Error DetectingCodes and Their Implementation," ComputerDesign, Vol. 10, pp. 53-59, Sept. 1971.

8. Kohavi, Zvi, Switching and Finite AutomataTheory, New York, McGraw-Hill, 1970.

9. Lin, Shu, An Introduction to Error CorrectingCodes, Prentice Hall, Inc., Englewood Cliffs,New Jersey, 1970.

10. Liccardo, M. A., "Polynomial Error DetectingCodes and Their Implementation," ComputerDesign, Vol. 10, pp. 53-59, Sept. 1971.

11. Peterson, W. W. and E. J. Weldon, Jr., ErrorCorrecting Codes, 2nd edition, The M.I.T. Press,Cambridge, Mass. 1970.

12. Shannon, Claude E., and Weaver, Warren, TheMathematical Theory of Communications, UrbanaThe University of Illinois Press, 1964.

13. Turin, George L., Notes on Digital Communication,Van Nostrand Reinhold, New York, 1969.

14. Yousif, Salah M.,"Some Aspects of Process Computerin Data Acquisition, Transmission and Control,"IEEE, Region VI Conference Proceedings, 1971.

CHANGING COMMUNICATIONS TECHNOLOGY

AND THE TELE PROCESSING BOOM

David G. Schutt

Pacific Telephone111 N. Market

San Jose, California 95113Phone: (408) 291-4609

Abstract

The healthy data communications expan-sion in California is an outgrowth of thehost of data processing vendors and userswho serve this area. New markets and newservices appear every day. Those who arenot using remote data processing now may wellbe large users of data communications in thefuture.

This teleprocessing boom not only in-creases the number of data communicationscircuits, but it also results in increasedtransmission speeds. Both new and existingcommunications common carriers are lookingfor ways to satisfy the voracious hunger forinformation transmission that the teleproc-essing market stimulates.

Concern for the ecology of computers andof communications is of primary importance.Three natural resources are basic to tae com-munications ecology:

(1) space,(2) bandwidth,(3) time.

Space resources are consumed by cables in un-derground ducts. Bandwidth resources areconsumed by microwave radio channels. Timeresources are consumed by transmitting sig-nals in a fixed length of time. Economicfactors heavily influence which resource isused.

The communications carriers strive touse their resources effectively and effi-ciently. This means there is a continuingdemand for devices that efficiently use avoice bandwidth channel for high quality,high speed data transmission. As technologyprogresses, the information transfer rate onvoice bandwidth channels has increased from1200 bits/second to 9600 bits/second and evenhigher on some circuits.

At the same time, second generation dataservices are becoming popular. They satisfya need for fast transmission speeds to permitcomputer load sharing, magnetic tape trans-mission and high speed facsimile reproduc-tion. In the past, such services generallyused more spectrum.

About the same time that wider bandwidthservices were growing, a time-division multi-plex system wae being introduced for voicebandwidth transmission in the Bell System.'This system, called Tl carrier, has had aprofound influence on the communications in-dustry. One might say tuat each voice band-width channel in a T system is trading timefor its equivalent bandwidth. That is, eachvoice channel has end-to-end control during

its particular sampling interval only.

Digital techniques are used to transmitthe voice samples. Consequently, high speeddigital data communications users now havethe ability to get from one location to an-other without converting an on-off (digital)signal to a band-of-frequencies (analog) andback to digital again at the distant end.2d

The digital network that the Bell Sys-tem proposes for service in late 1973 or ear-ly 1974 can be used to interconnect these Tcarrier systems to provide highly reliableand accurate digital data channels.4 An or-der of magnitude improvement in error per-formance over the present switched networkcan be expected. Figure 1 shows the inter-connection hierarchy for digital systems.

Equivalent

Number ofName VB Channels

BitRate(Mb/s)

Digroup 24 1.544

Super digroup 96 6.312

Master digroup 672 46.304

Jumbo digroup 8064 560.160

Figure 1 - Digital Hierarchy

TypeLineT1

T2

Digital channels will be provided byother means in addition to T carrier. A newdevelopment will enable the Bell System touse its extensive microwave radio network tomeet the rapidly rising demand for digitaldata service. In addition, a unit is underdevelopment to transmit 6.3 megabit/secondbit streams on coaxial cable.5

A digital data transmission network hasadvantages and disadvantages to both commoncarriers and users. For the foreseeable fu-ture, data communications channels will un-doubtedly'be a mixture of both analog and di-gital. When the signals to be tra-,smittedare already in digital format, dig_tal chan-nels and time-division multiplexing will beadvantageous if their use can be shared overa variety of services.2

References

1. K. E. Fultz and D. B. Penick, "Tl Car-rier System," Bell System TechnicalJournal, Volume 44, No. 7, pp. 1405-1451, September, 1965.

2. K. G. McKay, "Digital Communications--ATutorial," Bell Laboratories Record,pp. 279-284, October, 1971.

3. L. F. Travis and R. E. Yeager, "WidebandData on Tl Carrier," Bell System Techni-cal Journal, Volume 44, No. 8, pp. 1567-1604, October, 1965.

4. P. E. Muench, "Bell System Private LineDigital Data Service," IEEE 71 Interna-tional Convention Digest, pp. 214-215,March 23, 1971.

5. J. F. Gunn, "Digital Transmission on theL4 Coaxial System," Bell LaboratoriesRecord, pp. 51-55, February, 1970.

THE BACKGROUND, ECONOMICS AND APPLICATION OF THECASSETTE TERMINAL

Sheldon C. Bachus - University of California, Santa Cruz

Viewed historically, the technological advances in de-veloping complex computing devices has moved at a fargreater pace than the techniques for getting data intothem. The punched card, the prototype of which was firstused in the 1890 census, remains anachro..istically theprincipal communication medium between man and computer..Recent developments in source data automation, however,have provided an alternative to the punched card approach.This alternative, the cassette terminal, has significanttechnical, organilation, and economic ramifications.

Technically, the cassette terminal is identifiable by anarchitecture usually consisting of a keyboard, video dis-play screen, singular or multiple cassette rocorders, anda central micro-processor. The micro-processor performsa variety of functions in lining together the variouscompon,nts. These functions include data editing andsearching, arithmetic operations, matrix or "table look-ups", and data communication with a central computer orother terminals. Additionally, the cassette terminal canbe equipped with peripheral devices including printers,card readers, and mass storage units. In that the micro-processor is directly programmable via either the key-board or by stored cassette record, the cassette terminalbecomes a powerfUl tool for not only the capture of databut also for its ultimate disposition within the frame-work of the modern organization.

Little has been said by social scientists as to the impactof computers on modern organization. Correlatively,nothing has been said with respect to cassette terminals.Yet, the cassette terminal can potentially alter the'structure of every large centralized organization. Mostnotably the cassette terminal can serve as the arbiterbetween the forces of centralization and decentralization.That is to say, through its inherent flexibility, the cas-sette terminal can establish an equilibrium between thefrequently competing forces of organizational unity anddiversity. This equilibrium is most quickly identifiableat the middle management level of the organizationvlstructure. It is here that the demands of centralizedstandardization conflict with the innovative and personalvalues of the unit manager and his staff. The casnetteterminal provides an equilibrium between these forces byserving centralized information processing with standard-ized data inputs, and, concomitantly providing the unitmanager with independent control of data aggregation,display, and formating. Furthermore, it does this at aneconomical level competitive with the traditional punchedcard approach to data entry.

To establish the economic impact of the cassette terminal,a cost study was undertaken by the Santa Cruz campus ofthe University of California in the Spring of 1971. Thisstudy was-premised on three major hypotheses:

1. Hypothesi3 I. In an ,n.ganizational environment inwhich computer data is first manually coded and thenindependently keypunched or keytaped, cost saviugs canbe derived by automathg the coding process such thatthat process directLy produces the computer inputmedium.

2. Hypothesis II. If the validity of Hypothesis I holds,then it can be further demonstrated that the derivedcost savings will vary proportionately with the magni-tude of the data being coded.

3. Hypothesis III. Additional cost savings can be gen-erated by automating office procedures not directlyassociated with the creation of computer-compatibledata.

4.5

To test these hypotheses, an organizational environmentwas quantified using various workload measures. Thistest environment consisted of the campus Financial AidOffice and the integration of its operations cycle intoa computerized, Universitywide f..nformation system.Findings of this study showed that with respect to Hy-pothesis I, onlv minimal savings of 3.61 would be de-rived over traditional data eAtry techniques if acassette terminal were implemented at a low enrollmentlevel of 4,100 students. However, in support of HypothesisII, significant savings of 37.5% would occur as campusenrollment increased. In testing Hypothesis III no sig-nificant cost savings were found. It should be noted,however, that the organizational procedures in this lastcase were evaluated using a cassette terminal without full_arithmetic.support, high-speed data search, and "tablelook-up". It is expected that further studies involvingthese factors will demonstrate additional savings usingthe cassette terminal approach.

42

COMPUTATION AND COMMUNICATION TRADE-OFFS IN MILITARY20MMAND AND CONTROL SYSTEMS

Dr. N.E. WillmorthSystem Development Corporation

2500 Colorado AvenueSanta Monica, California 90406

213-393-9411

DoD is just now in the process of replacing a largenumber of obsolete small and medium scale ftrst andsecond generation computers with modern, powerful,cost effective computers. Conceptually, these comPi.terswill form the hearts of interactive, remote job entrycomputer utilities that will place an unprecedentedload upon existing digital data tram Ission facilities.In short, the tremendous technologica. explosion indigital data processing capabi/ities may be creatinga mismatch between processing and transmission costs.The CACTOS Project was created, under the sponsorshipof DoD's Advanced Research Projects Agency, toinvestigate the cost effectiveness of various trade-offs among computation and communication capabilitiesthat might lead to the design of optimal teleprocess-ing system networks.

Potential sources of cost effectiveness in designingalternative digital data systems lie in the economiesassociated with advancing technology, increasing scale,improving quality, specializing and simplifyingprocesses, integrating functions, and minimizingnetwork topologies.

It would appear that taking advantage of the potentialfor technological development yields the most returnfor cost effectiveness comparisons. Costs per unitof operation for central processing units have beenchopping by an order of magnitude about every sixyears. For transmission facilities, the decreasein costs have been obscured by the pricing policiesof the public utilities and the FCC, but appear toapproach an order of magnitude in about 20 years. Thedevelopment of storage media and terminal dnvices havenot progressed quite as rapidly, but rapid advanceappea-s certain for the future.

The economies of scale are the second most promisingsource of cost effectivity, but tend to be correlatedwith technological advance. These two potentialeconomies provide the impetus for many extensions andconsolidations of digital data processing systems.The economies of scale seem to vary considerably withthe task for central processing units, varying fromeconomies greater than Grosch's law to approximatelystraight line relationships. Potential economiesof scale for commq.niCation systems see* large, butagain are somewhat obscured by public pricing policies.

The economies of quality lie in improved reliabilityand reductions in error rates. The advantages ofqUality are obvious and very high quality can beobtained through system redundancies and errordetection and correction techniques, but thesetechniques tend to Se expensive. As vi,:n scale, thecost effectivity of quality is correlated withtechnological advance. One of the most prothisingtechnological advances for quality of data trans-mission is pulse code modulation (PCM) and timedivision multiplexing. All digital systems based on

4.6

43

LSI logic and PCM/TDM techniques promise large gainsin quality at considerable reduction in costs.

The economies of specialization and integrationlie largely in avoiding the overhead costs ofinitializing, terminating and bookkeeping forcomplex job mixes and in creating standardizedprocessers and processes that are perform moreefficiently than general purpose machines andprocedures. In this, specialization trade-offs arein contention with the economies of scale. However,5uture systems may depend upon gaining efficiencythrough multiprocessors and distributed logic(i.e., intelligent terminals and computerizedconcentrators and switches).

The economies to be found in minimizing networkcosts present a complex problem to system designers.Optimum routing may involve least dollar costs,least links, most reliable or least distance as wellas traffic load considerations. Optimum locationsfor nodes and optimum connections present otherproblems. There are so many factors to consider inevaluating alternative computation and communicationnetwork configurations that general trade-offfunctions are difficult to derive.

Assessing economies for military command and controlsystems is complicated by the multiplicity of theperformance criteria to be satisfied. Throughput,response time, reliability, and vulnerabilityare only a few of these. The benefit to be assignedto a particular performance criteria varies fromsystem to system, depending upon the system mission.MUch further investigation will be required beforegreat precision in evaluating computation andcommunication trade-offs is realized.

SYNERGETIC MEASUREMENT TECHNIQUESFOR DATA TRANSMISSION

R. M. TweediePacific Telephone

Room 606, 111 N. Market StreetSan Jose, CA 95113

408-291-4739

Abstract

The transmission of data from one loca-tion to another requires a transmission sys-ten or circuit. These circuits are composedof one or more transmission links, each ofwhich has electrical properties th=.t willmodify the signal to some extent. It there-fore becomes necessary to have some way tomeasure the amount of these signal modifica-tions. Industry standards have been estab-lished for the majority of the different mod-ifying circuit properties. Some of the pa-rameters reauire measurement techniques notpossible to implement without special testequipment. A number of the misunderstandingsencountered between the Data and Communica-tion industries are directly traceable toboth not completely understanding these spe-cialized measuring instruments and the cir-cuit parameters they are designed to measure.

One of the most common offenders is im-pedance. The effect of impedances other thanthat specified for the Telephone Company in-terface on circuit loss measurements and gainfrequency response is a frequent problem. Aninteresting example of this occurred recent-ly. There was a difference of 1.8 dB betweenthe circuit loss measurements of the datauser and the Telephone Company. One was us-ing a meter with a high input impedance andmeasuring bridged across the line of the cir-cuit (the modem impedance specification was600 ohms at 1000 hertz). The other used a600 ohm instrument to terminate the circuitin place of the modem and measured the cir-cuit loss. The 1.8 dB discrepancy in meas-urements was resolved when the impedance ofthe modem was measured and found to be 460ohms and highly reactive at 1000 hertz. Atermination such as this would also cause se-vere errors in gain frequency response meas-urements.

The practice of using a data signal tomeasure circuit loss has caused serious mis-understandings. With many data line signalsbeing nonsinusoidal, the.meter will give dif-ferent readings depending upon whether thedetector is peak, peak-to-peak, average re-sponding, root-mean-square or root-sum-square. While each of these detectors may becalibrated to read the same on sine waveform,there are considerable differences betweenthem (on rectangular pulses for example).

Another common problem is the measure-ment of circuit noise using a wide bandwidthresponse meter. One customer measured cir-cuit noise in dBm using a popular AC VTVM.With a response of greater than 1 MHz, themeter actually measured the RF field of anearby radio station. Even without nearby RFfields, we have seen differences of greaterthan 30 dB between band-limited noise metersand wideband AC VTVMs. High frequency noise

4.7

not only has a greater effective noise band-width than voice-frequency noise sets, butthe cable crosstalk is much worse at higherfrequencies due to the cable capacity show-ing less capacitive reactance at high fre-quencies. Switching noise, analog and digi-tal carrier systems all have considerablehigh frequency components that do not affectvoice-frequency systems. The communicationsindustry noise test sets have filters ar-ranged for different weightings. The mostcommon of these have roughly 300 to 3000 Hzpassband.

A more subtle measuring problem recent-ly was discovered with phase jitter. Twophase jitter meters of the same make andmodel gave identical readings at one jitterrate and yet differed by 100% at anotherjitter rate. This was due to a difference inthe low jitter rate response of the two in-struments.

Each impairment such as envelope delaydistortion, noise, phase jitter, phase hits,gain hits, drcpouts, harmonic distortion andfrequency shift has its particular measure-ment pitfall(s) . It is imperative that ourindustries make every effort to understandthe peculiarities of the language and equip-ment of the other if we are each going to doan efficient and effective job.

HUMANITY IN MEGABITS AND MICROWAVES

(Introduction to a seminar session)

By

Gerd D. Wallenstein, Consultant298 Austin Ave., Atherton, Ca. 94025

(415) 326-1902

ABSTRACT

The quesi.lon has been asked: What is thecomputer/communications marriage's Ampacton society? Attempting to find answers,we must first seek some useful definitions.These concern society and values, inparticular.

Society-. What society are we talkingabout? Is it the conglomerate of millionswhose single common denominator isnationality? Is it a more specific culturewithin the national society, such as thewhite upper middle-class in the midwesternUnited States?

Reaching beyond the arbitrary limitu ofthe nation- is it the internationalsociety of futurists, for example?Appropriately, at this point,, we mayask whether any of these societies is tobe considered as it appears now, or as itmay appear at some time in the future.

For each of the societies so defined, animpact would be discernibly _different.Very likely, for each society we mightfind multiple impacts of particularcomputer/communications patterns. When wesummarize, we would have a large matrix,relating societies to possible impactpatterns. Until we have that matrix andtested methods to apply it, we should bewary of impact generalizations, as wellas of exag,zerated conclusions drawn fromisolated, narrow-focus impact studies

Values. The continuous development ofcomputer/communications complexespostulates that megabits married tomicrowaves represent values in their ownrights. The opposition to this viewfrequently emphasizes dehumanization,meaning a loss of human values.. Perhapsboth views are too one-sided. We mightlearn from our experience with ecologyand formulate our lesson as. followss

Any definition of optimizing the humanlife experience- and it is clear thatthere are many such definitions- centerson the concept of balance. When anycontributing element iu allmaed to growbeyond, a certain critical relationshipto other elements, the conditions for

5.1

balance are seriously disturbed. Thesame seems true when the oppositehappens- that is, a reduction of acontributing element below a certaincritical value.

Disturbance of the balance eoes notnecessarily mean degradation in a humanvalue system- but it does mean that anew balance needs to be found. In anincreasingly man-msde environment, thatbalance may not come naturally. Mankindwill have to work on it consciously.

Applying this concept to the computer/communications syndrome, it seems topoint the way to a most urgent task athand. That task,is the study of arequired balance of the rational andirrational human dimensions. Technologyprovides us with the fruits of ourrationality; the taste and the quantitiesof these fruits are rapidly changing.What can be done to the fruits of ourirrationality, to restore and maintainfor us a balanced diet? This questionneeds to be explored, no matter howelusive the answer may be. Possibly wemay find the outlines of an answer, inthe very act of the exploration. Afirst, useful step in that directionmight be an exploration of their ownirrationality on the part of those whopractice the rational technology. Wemay discover a significant relationshiphere. If nothing else, we might experiencemore recognition for the irrationalhuman side- a prerequisite of the searchfor balance.

Con-lusion To evaluate impacts onsocieties, definitions and explorationof human society and value systems areneeded. This is a continuous task sinceimpacts are continuously changing. Atgiven points in time, a specific impactmay be predicted or statisticallyevaluated. While some of this narrow-focus can be very useful, much of itmay be comparable to evaluating theimpact of colliding cars on a crowdedhighway. The statistics are reliableand the predictions reasonably accurate-but they Contribute little to a betterbalance of traffic needs and facilities.

References

Wa1lenstein, Gerd. "The Humanizationof Technical Man", CyberneticSystems Paper, San Jose State College,1971.To be published in 1972.Includes references from 20 authors.

45

SOCIETY: KEY ELEMENTS FOR THE FUTURE

by Arnold MitchellSenior Social EconomistStanford Research Institute

One of many ways of studying society involvesa "values approach." This approach takes theview that the principal moving forces in contem-porary American society are the changingneeds, values, and beliefs of key segmentsof the population; that this nation is in themidst of a truly major phase-change into a"higher" set of values; that the emerging post-industrial future will be based upon these newpatterns of needs, values, and beliefs; and thatcurrent trends can lead to the kind of pluralisticand prosperous future most of us say we want.

Society can be richly--even el.=.santly--describedin terms of some number of groups of people sharingcertain patterns of needs, values, and beliefs(NVBs). These NVB patterns can be arrayedhierarchically in terms of levels of developmentas described in the schemata of human growthproposed by modern personality theorists.

Each of these NVB groups pursues differentaims in different styles. Core needs evoke supporZ-ing values and beliefs and vice versa. And so aperson (or a nation or an institution) in evolvingthrough the stages of growth takes on profoundlydifferent interests and llfe patterns as he grows.A Poverty-stricken man, for instance, may devotealmost all his time to surviving physically.Dog-eat-dog morality animates him. However, as

his food and shelter needs are satisfied he turnshis attention to protecting what he has. Suddenly

respect for law and order replaces the earlierdog-eat-dog style. As he progresses, his centralinterests may eventually turn to accumulatingmaterial things as symbols of achievement. At

first, his wordly goods are evidence that ir) hasrisen above the poverty level. Later, they becomesymbols of high status in a society which evaluatesmen by their wealth. The man's style becomesacquisitive, driven, and competitive.

There are influential groups now in the Americansociety which have passed beyond these stages.They pursue goals which are beyond the imperativesof economic prestige. Although their numbersare still small, they tend to hold positionsof disproportionate importance. When young,they tend to be among the student leaders; whenolder, they often appear in upper professionaland management posts. This group--which we callthe unfolders--seems to be the cutting edge of thefuture.

This way of looking at society suggests that theseeming chaos of societal trends, the about-faces,the unheralded events, the surprises unforseen byeven the most acute observers stem from the emergenceof a critical mass of unfolders within a societydominated throughout its history by materialistic,scientistic, deficiency-driven concerns.

If this interpretation is anywhere near themark, there are at least three types of futures thatcould result.

First, it is certainly possible that the forces ofinertia, status quo, and traclition could become soalarmed--even shocked--that they would impose ironsuppression on society, resulting in some variant of theauthoritarian state. A second reaction could be thatof tokenism in accepting the values of unfolders.This seems reasonable to many on the grounds that thisnation would be foolish indeed to discard wholesalethe NVB system that has served so well for so long.

But need the baby be thrown out with the bathwater? A third kind of future might be built byselecting what is healthiest from the old and thenew. So, as a nation, we would ask what human needs,values, and beliefs we wish to foster in addition tothose provided for within the more limited frameworkof achievement values. The question :Is what we wish toadd, not what we must lose; it is a question of wherewe want to go, as well as what we choose to flee from.

What, it seems to me, we should be aiming for isa "synergy society," to use Ruth Benedict's phrase.The synergy society is one in which the act of eachindividual serves not only his own good but that of thesociety. As a profound wit said, it is a society in whichvirtue pays. The synergy principle should do for thepost-industrial society what the marketplace principledid for the industrial world: it should providea mechanism by which the myriad, short-term, dailydecisions taken in isolation by people in their personaland work lives add to a healthy and workable long-termdevelopment of society as a whole.

But how might the "values approach" to socialanalysis be implemented?

One would first wish to identify some manageablenumber of NVB sets that would adequately describe theAmerican people. These clusters of NVBs--perhaps tento twenty of them--can be visualized as layered strataarranged hierarchically within the society. One wouldthen seek to correlate with these NVB groups moreusual characteristics such as SES, demographicattributes, economic and political characteristics andso forth. Such information would provide one approachto the crucial task of forecasting NVB distributionsin the future. In addition, depth interviews withmembers of each significant NVB group would ferret outtheir emerging and receding values, social concerns,

5.2

hopes, fears, dreams, plans, life styles, andso on. These data would be analyzed forqualitative shifts within NVB patterns,changing numbers in each cluster, trends indiscrepancies between expectation and reality,alterations of power distributions, etc. The

influence of environmental factors would haveto be systematically considered. From thesestudies should Come better Intimations thanwe now have of nascent social trends, theirpoints of origin, their proponents andopponents within and across NVB groups,their timing, force, style of expression,direction of development, and so forth.

Studies of this sort should have greatutility in a variety of research areas.For example, each NVB group could bestudied for its sense of what constitutesthe good life. Some sort of nationalquality of life index might ultimately bebuilt up out Pf these dnta. If the

approach could provide a "social radar,"it should be, helpful to organizationsconcerned with anticipating and respondingto social pressures. Application of theapproach within institutions shouldfaCilitate effective management and improvedorganizational development. Finally, on aanictal level, the kinds of insight providedhy Nr4 studies should be useful in analyzing

%i and .7subcultural goals, in identifying

so.:.181 hot-spots and hence in setting program

pyioritikes, and--of course--in settingpolicies aimed at "inventing" the

futares we select.

And so--to revert to the title of.thistalk--it could well be that the key element .forthe future of this society is the kind of peoplewe are and have the wisdom tc become.

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47

THE SOCIETAL SIDE OF THE WIRED CITY

With the existing levels of communication awarenesstoday, there is considerable effort being devoted tothe perusal and conjecture of the role communi-cation plays in creating social change. While somelay all of the ills of today at the footstep oftelecommunications technology (TV particularly),others look to the emergence of the "Wired City"for the salvation of mankind.

In spite of its accepted mystique, there seems tobe no explicit definition of a "Wired City". Thewords appear to be only a term used by acommunity of "experts" for their own purposes.

In reality cities have been wired for both powerand communications for almost a century.

From the context of use the implicit meaningsuggests Wired City is a broadband systemlikened to that used for CATV distribution. It iscontended that the cliche really constitutes asecurity blanket under which the lack of compre-hension and knowledge needed to design anadequate telecommunication systems for the futureis hidden.

This paper is intended to provide a broad-brushlook at many of the social factors which arefelt to be relevant to communications/telecom-munications understanding. The controllingelements for any "Wired City" are social and nottechnological in nature. Therefore pre-occupationwith technology in advance of behavioural under-standing is bad.

In spite of what the protagonists of "Wired City"might infer by the .offered technologicalsolutions, relatively little exploratory work intelecommunications has been done in an effort tounderstand more of the communications process.

The soeietal impact of the various/communicationsmedia can be judged by the proliferation andutility as perceived by the users.

What is the relative prominence you personallywould give in your own home to the followingcommunication media.

TelevisionRadioTelephoneFilm ProjectorPhonographNewspaperMagazinesBooks

The order may vary a bit, but television andtelephone probably consistently head the list ofhouseholder preferences.

In the future, additions to this list will appearand satisfy further needs. The prediction ofthese additions requires more understanding offuture social behaviour. Appropriate technologywill then be applied. If it is non existent atthe moment it will be invented for the requisiteneed.

In other words teChnology will not determine howcities f the future will be wired. To plan forthis t. must understand impending changes inthose areas considered to be cultural and social.These areas constitute that part of behaviourwhich is influenced by custom and learned. Thusit can be changed to permit need satisfaction.

For example when automobile transportation tech-nology was introduced new codes of behaviourevolved. The early automobile drivers soondeveloped rules of the road by concensus thesebecame distilled as custom and up with both socialstigmas and taboos. Highway construction anddesign now reflects this.

In this context - wired cities will end up con-figured to match the behaviour patterns of thepeople which is self evident.

Further proof of the societal nature of communi-cation systems has been identified by GordonThompson, a scientist, philosopher at Bell-NorthernResearch in Ottawa. He has analysed theevolution of telecommunication innovation, andthese common patterns related to displacement ofone technique by another emerged.

Each succeeding invention increased.

1. The size of exe shared common communicationspace

2. The ability to access stored information3. The ease with which concensus could be

established.

Recently it is becoming evident that there aretwo others. A fourth - the number of wealth-creating opportunities is increased, eg. therange of available options for commercial actionis increased through the ability to communicate.A fifth - relates to an increase in the sensiti-vity of a culture to the consequences of remoteactivity.

All aspects o: these measures involve informationtransfer between originators and consumers ofinformation. It is evident that the distributionsystems must recognize that Communications hasthese dimensions - it can function in real ordelayed time. A real time system can provide forinteraction or not depending on usage needs.

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418

The storage of large quantities of informationis a major physical problem whether in homes,libraries, or businesses. Computers nowprovide new capabilities for information storagewhich is beginning to be used extensivelythroughout the business community. Thiscapability will eventually be extended to thecommunity at large.

The person accessing the stored informationhas a usage related set of problems.

1. The information must be stored in a way inwhich it can be retrieved easily.

2. The stored information must be effif:dentin terms of the users behaviour.

3. The form in which it'is to be used whenit is retrieved requires consideration ofthe user and his preferences in terms ofhis utilization function.

4. The relevance of the offered informationto the needs of the user.

Considerable time is being spent todaytalking about computer systems and informationbanks without specific reference to the socialprocesses which would govern the use of thebanks. There can be no effective designand development of these systems until thistakes place.

It must also be recognized that all existingcommunication systems which have had a majorsocietal penetration and impact-have alsogenerated a significant amount of standardi-zation in the technology. Standardizationis the result of an implicit concensus betweenthe manufacturers and users after a certainamount of experience with operating systems.This experience leads to modification. Theprocess proceeds with diminishing utility untilevolution ceases and standardization occurs.Language is the most evident of the stand-ardization events. Even so, there is roomfor major variance between large population/ethnic entities, and within that, furtherroom for individual variation.

This all relates to the process of concensusforming which we have noted earlier as oneof the four factors in the determination ofthe communication media itself.

Within the context of discussion on "Wired City"it must be remembered that one of the featuresof society today is the mobility of people.One might argue that this reached is zenithwith the automobile but modern aircraft havedone nothing but expand the horizons. Thismobility is changing the community of interestof peoples and with this change goes some ofthe foundations of the social environmentunder which many of us have lived. We findourselves in the position of knowing that our"community of interest has changed". Theearly reality in telecommunications was acommunity closed environment. Within itsphysical boundaries an individual had histotal set of relationships.

This has changed significantly in any community ofmoderate to large size. Failing this a largersegment of the population has been mobile and extendeditself beyond the boundaries of the physical communitywhich have been reflections of physical or politicallimits. In most cases it has been the,politicallimit which has defined the community.

Within that community in terms of the interpersonal4 relationships individuals with mobility have

established a pattern of relationships significantlydifferent from the definitions of political communitieswithin which the physical aspects of life are limited.(houses, voting rights etc).

In conclusion - there can be little doubt thattechnology and behaviour are related. However, in

terms of future systems the controlling variableis the programming content itself. Beyond this, thetechnology used is influential only in terms ofits efficiency. There is a degree of comprehensionrelated to the technique used to disseminate it.

5.5

Author: D.M. AtkinsonBell CanadaMontreal

119

ECONOMICS OF PRIVACYKen R. WaltersPacific Telephone Co.140 New Montgomery St. Rm. 408San Francisco, California 94105

American business is largely conducted bystockholder-owned corporations which operatefor a profit. These business corporations maybe divided into three major categories:

(1) Private corporations which engagein manufacturing, servicing, and mercantileactivities that are motivated by competition.It is this "private" that appears in the title.The thought I will try to convey is how theBell System will look in its new role ascompetitor.

(2) Financial corporations such as banksand insurance companies.

(3) Public utilities which provideindespensible services under monopolyconditions with government regulation ofprice, profits and service quality.

A T & T is the head of a family ofregional operating telephone companies, eachwith its own president and board of directors.While A T & T owns the stock in most of them,the companies themselves are responsible formany critical, autonomous decisions, particu-larly regarding problems associated directlywith their local operations.

A T & T also owns the Western ElectricCompany which manufactures or purchases mostof the supplies and equipment used by theoperating units, and jointly with WesternElectricit owns Bell Telephone Laboratories.

This basic structure has existedunchanged for the better part of a century.The basic structure and policy foundations ofthe Bell System were the brain children of oneman - Theodore N. Vail. Vail was the firstgeneral manager of the original Bell TelephoneCompany organized in Boston in 1878 and thefirst resident of A T & T which was incorpor-ated in 1885.

Vail patterned his structure of thetelephone system after that of an existinginstitution that had more than proven itssocial and survival values - our own federalgovernment. To Vail's mind, the "Federal"structure was that it provided for aneffective division of responsibilities, andthereby an efficient means of managing verylarge resources. It was the goal of thefledgling telephone industry to aventuallyprovide voice communication to pointsthroughout the United States and as Vailput it, "by cable and other appropriatemeans to the rest of the known world."

Before his dream could be realized, _however, something had to be done about theneedless costly and wasteful duplication offacilities that existed then as a result ofcompetition between telephone companies

5.6

operating in the same geographic areas.Vail's solution was, "One System, One Policy,Universal Service". He campaigned vigorouslyfor - and eventually won - government accept-ance of what came to be known as the "commoncarrier concept." This concept whicheliminates unneeded and uneconomical dupli-cation of facilities has three virtues:Responsibility, Compatibility and Coordination.

First it pinpoints the responsibility forservice so that regulatory bodies can moreeffectively represent the telephone-usingpublic.

A second virtue of the common carrierconcept is that it helps insure a closecompatibility among the billions of intricate,interdependent parts that comprise the communi-cations network.

The third virtue of the common carrierprinciple is that it permits a coordinatedresponse to the communications needs anddesires of telephone users, through appli-cation of what has come to be known as thesystems concept.

The outstanding economic characteristicof public utilities is that they can operateat greater efficiency as monopolies. Publicutilities operate at lower unit costs undermonopoly that under competition by eliminatingcostly duplications of facilities and byachieving decreasing average unit costs asutilization increases.

Two examples of questions confrontingthe communications industry management rightnow are:

(1) What should the Bell System do torespond to the challenge of a competitor whohas won FCC approva?, to provide specializedcommon carrier services between two of ourlarge cities? Our rates are based on nation-wide average costs. The charge is the samefor equivalent distances regardless of whetherthe route carries heavy traffic and is there-fore a low-cost route or a light traffichigh-cost route.

You can see that nation-wide averagepricing-has been a major factor in extendingcommunications to the remotest parts of ourgreat country. Should we abandon nation-widepricing and price instead to meet or beat ourcompetitor's prices, as we very well can onthe basis of the costs we experience betweenthese two cities alone? If we meet thecompetition and cut our rates on that routealone, won't that burden the remainder f ourcustomers with higher costs? On the otherhand, if we don't meet the competition, isn'tit inevitable that we would lose business andtherefore some of the economies of scale thatpermit us to keep our charges low to all ourcustomers?

(2) Should the.Be17. System charge tiiecustomer what it costs to install his tele-phone? Mr. Vail's answer to that questionwas no. In his drive toward universal service,he believed that initial charges should be

,17

kept low and that the costs of installationshould be recovered from our monthly charges.

In summary, what effect will competitionhave on the communications industry? LongRange Incremental Costs and Usage SensitivePricing will become new phrases in (Dorvocabulary. Prices will become more closelyrelated to costs, but the greatest changewill be in the general attitude. It willbecome more "marketing-oriented" by under-taking more market research programs,experimenting with new innovative servicesand generally being more responsive to:Joecial customer requirements.

ABSTRACT

THE IMPACT OF CYBERNETIC AND COMMUNICATION TECHNOLOGIESON EDUCATION

A panel presentation byREYNOLD B. JOHNSONEDUCATION ENGINEERING ASSOCIATES

Educators, education institutions and students arefacing increasing problems of cost and effectiveness.The explosion of information, the proliferation ofcareers and vocations and the requirements of ourculture for more highly trained and educated profession-al and non-professional workers have placed demands onour educational institutions which cannot be met by themere extension of our conventional teacher-classroomeducation system. With proper engineering, the technol-ogies of communication and computers can be shaped intotools that will greatly improve the teacher's effective-ness and at the same time meet the diversity of learningneeds of students. Far from dehumanizing the learningenvironment, the proper exploitation of technology canrestore human interaction and learning in the affectivedomain to our schools.

This paper will discuss cybernetic and communicationtechnologies and the utilization of these technologiesto improve the quality of life in the learning environ-ment.

Abstract

MACHINES AND TEACHERS

Ralph ParkmanProfessor of Materials Science

San Jose State CollegeSan Jose, California 95114

Everyone is an expert on education. Each of usfeels he knows what there is to applaud or to rejectin the school systems through which he has passed.A concern about freedom vs. authority is one of theissues most often addressed in dialogues aboutpublic education; and maay of the discussionsrevolve about the potential of modern technologicaldevices and methods to free the student from thelock-step "tyranny" of mass instruction, so that hecan proceed in the direction and at the pace mostcongenial to his abilities or interests. It is alsoordinarily assumed that the teacher, too, willbenefit from the employment of these technologiesby being freed to pass on to the machine many ofthe onerous chores of record keeping and drill orpractice type of instruction at the very least;thus permitting time for concentrating on the morecreative aspects of the instructional process.

The simpler forms of technology, as teachingaids, have long been a part of the educationalpicture, but there is now the often expressed hopethat the computer will soon be capable of offeringa novel dimension to education, bringing theconcept of individualized instruction much nearerto reality. Computer systems, as adaptive deviceswith the capability for operating in a logical mode,have indeed shown some promise of reactingeffectively to differences in response amongindividual learners. However, most of thesuccessful experivnits reported in the literaturehave involved small groups of researchers workingwider mbre or less controlled conditions with arelatively few students out of the total schoolpopulation. Extending the limited experimentalfindings, contradictory as they sometimes are, tolarge public school systems involves problems ofsuch magnitude and complexity that no one can yetsay with certainty what effect the,new educationaltechnologies will have when considering the overallobjectives for a public school system.

This paper will cons'ider some of the practicaland philosophical problems related to applyingtechnologies to the educational process.

5.7

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