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WELCOME TO THE RISING TECHNOLOGY

“ASYMMETRIC DIGITAL SUBSCRIBER LINE”

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INDEX

CHAPTER 1

INTRODUCTION

1.1 DIFFERENT VARIANTS OF DSL 1.2 WHAT IS ADSL 1.3 WHAT ARE THE BENEFITS

CHAPTER 2

FUTURE OF ADSL

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CHAPTER 3

A.D.S.L. CAPABILITIES

3.1 FREQUENCY RESPONSE

CHAPTER 4

ADSL TECHNOLOGY

CHAPTER 5

METHODS TO SPLIT THE SIGNAL

5.1 CARRIER LESS AMPLITUDE5.2 DISCRETE MULTITONE

5.3 PASSIVE FILTERS

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INDEX…

CHAPTER 6

ADSL EQUIPMENT

CHAPTER 7

DISTANCE LIMITATIONS

6.1 DSL EQUIPMENT DSLAM

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CHAPTER 8

INSTALLATION ISSUES

CHAPTER 9

APPLICATIONS

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CONCLUSION

&

REFERENCES

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CHAPTER #01

INTRODUCTIONPAST DECADE HAS SEEN EXTENSIVE GROWTH IN THE TELECOMMUNOCATION INDUSTRY

POPULARITY OF INTERNET & OTHER DATA COMMUNICATION SERVICES HAS INCREASED

MAJORITY OF INTERNET USERS ACCESS THEIR SERVICE VIA MODEMS CONNECTED TO P.O.T.S.

P.O.T.S. WAS DESIGNED FOR VOICE TRANSMISSION AT FREQUENCIES BELOW 3 KHz

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TO INCREASE PERFORMANCE OF NEW ONLINE SERVICES, THE BANDWIDTH HUNGRY PUBLIC MUST CONSIDER OTHER OPTIONS

TECHNOLOGIES, SUCH AS I.S.D.N. OR CABLE CONNECTIONS, REQUIRE SPECIAL CABLING

A P.O.T.S. CONNECTION PROVIDED AN ADEQUATE MEDIUM FOR RELATIVELY SMALL AMOUNTS OF DATA THAT REQUIRED TO BE TRANSMITTED

SO THE EXISTING SYSTEM WAS THE LOGICAL CHOICE OVER SPECIAL CABLING

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1.1 DIFFERENT VARIANTS OF DSLH.D.S.L. IT IS THE PIONEERING HIGH SPEED FORMAT, BUT NOT COMMERCIALLY VIABLE OPTION DUE TO ITS NEED FOR 2 TWISTED PAIRS & DOESN’T HAVE SUPPORT FOR NORMAL TELE PHONE SERVICES

S.D.S.L. IT IS SYMMETRIC DSL OPERATES OVER A SINGLE TWISTED PAIR LIMITED TO SHORT DISTANCES SUFFERS N.E.X.T.

I.S.D.L. STANDS FOR I.S.D.N. DSL

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SIMILAR TO I.S.D.N. TECHNOLOGY LACKS SUPPORT FOR ANALOG VOICE

V.D.S.L.VERY HIGH BIT RATE D.S.L.

REQUIRES SHORTER CONNECTIONS THAN ARE GENERALLY PRACTICAL

A.D.S.L.MOST PROMISING TECHNOLOGY

SUITABLE FOR PERSONAL BROADBAND REQUREMENTS

ALLOWS SAME CHANNEL TO STILL ACT AS A TRADITIONAL SERVICE

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1.2 WHAT IS A.D.S.L.A MODEM TECHNOLOGY

CONVERTS EXISTING TWISTED PAIR TELEPHONE LINES INTO ACCESS PATHS FOR MULTIMEDIA & HIGH SPEED DATA COMMUNICATIONS

CAN TRANSMIT UPTO 6Mbps TO SUBSCRIBER

832 Kbps IN BOTH DIRECTIONS

EXPANDS ACCESS CAPACITY BY A FACTOR OF 50 OR MORE

IT ALLOWS MORE BANDWIDTH DOWNSTREAM THAN FOR UPSTREAM

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USERS OF THESE APPLICATIONS DOWNLOAD MORE

INFORMATION THAN THEY SEND

A GATEWAY IS COMMONLY USED TO MAKE AN ADSL CONNECTION

IT IS WIRELESS

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1.3 BENEFITS OF A.D.S.L.PROVIDES HIGH SPEED INTERNET ACCESS USING REGULAR TELEPHONE LINES

CONNECTIVITY-ALWAYS ON

DATA SECURITY

EASE OF USE

NO DIAL-UP IS REQUIRED

SPEED IS UPTO 25 TIMES FASTER THAN ANALOG MODEMS

CHAPTER #02FUTURE OF A.D.S.L.

ADSL will play a crucial role over the next decade or more as telephone companies enter new

markets for delivering information in video and multimedia formats. New broadband cabling will

take decades to reach all prospective subscribers. Success of these new services will depend on

reaching as many subscribers as possible during the first few years. By bringing movies, television,

video catalogs, remote CD-ROMs, corporate LANs, and the Internet into homes and small

businesses, ADSL will make these markets viable and profitable for telephone companies and

application suppliers alike.ADSL Capabilities

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CHAPTER #03ADSL CAPABILITIES

oADSL MODEM CONNECTED TO EACH END OF TWISTED PAIR TELEPHONE LINE

o3 INFORMATION CHANNELS ARE CREATED :-

o1). HIGH SPEED DOWNSTREAM CHANNELo2). A MEDIUM SPEED DUPLEX CHANNELo3). A BASIC TELEPHONE SERVICE CHANNEL

oADSL GUARANTEES UNINTERRUPTED TELEPHONE SERVICE EVEN IF ADSL FAILS

oDOWMSTREAM RATES DEPEND ON :-

o1). LENGTH OF COPPER LINE

2). ITS WIRE GAUGE

3). PRESENCE OF BRIDGED GAPS

4). CROSS COUPLED INTERFERENCE

LINE ATTENUATION INCREASES WITH LINE LENGTH & FREQUENCY

LINE ATTENUATION DECREASES WITH INCREASE IN WIRE DIAMETER

18 POTS & A.D.S.L. DATA

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CHAPTER #04ADSL TECHNOLOGY

DEPENDS UPON ADVANCED DIGITAL SIGNAL PROCESSING TECHNOLOGY & ALGORITHMS

OUTSIDE - ADSL LOOKS SIMPLE

INSIDE- MIRACLE OF MODERN TECHNOLOGY

IT CONSISTS OF :- TRANSMITTER & RECEIVER…..

1).TELEPHONE EXCHANGE

2). SPLITTER

3). DSLAM , ISP

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4).SPLITTER

5). ADSL MODEM

6). COMPUTER

7). PHONE, FAX

FDM-ONE BAND TO UPSTREAM OTHER TO DOWNSTREAM

DOWNSTREAM-:TDM; HIGH & LOWCHANNELS

UPSTREAM-:CORRESPONDING LOW CHANNELS

OVERLAPPING REMOVED BY ECHO CANCELLATION

BLOCK DIAGRAM

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FREQUENCY RESPONSE OF ADSL

CHAPTER #05METHODS TO SPLIT THE SIGNAL

1). CARRIERLESS AMPLITUDE / PHASE (CAP)

TELEPHONE SIGNAL DIVIDED IN 3 PARTS

i. VOICE CONVERSATIONS- 0 TO 4 KHz (POTS CKT)

ii. UPSTREAM CHANNEL-25 TO 160 KHz (FROM USER BACK TO SERVER)

iii. DOWNSTREAM CHANNEL- BEGINS AT 240 KHz (FROM SERVER TO USER)

INTERFERENCE MINIMISED

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2). DISCRETE MULTITONE

DIVIDES SIGNAL INTO 247 SEPARATE CHANNELS,EACH 4KHz WIDE

EQUIVALENT TO GETTING 247 MODEMS

SIGNALS SHIFTED B/W DIFFERENT CHANNELS

MORE COMPLEX THAN C.A.P.

MORE FLEXIBLE

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3). LOW PASS FILTERS

BLOCK SIGNALS ABOVE CERTAIN FREQUENCY

ALL CONVERSATIONS- BELOW 4 KHz

LPF’s DESIGNED TO BLOCK SIGNALS ABOVE 4KHz

PREVENT DATA SIGNALS FROM INTERFERING WITH STANDARD TELEPHONE CALLS

ADSL EQUIPMENTSIt uses two pc’s of equipments one at the customer end and one at the internet services provider At the customer location there is DSL transceiver also called as “DSL MODEM” and ATU-R too.

DSL service provider has a DSL access multiplexer(DSLAM ) to receive customer connection.

The transceiver can connect to the customer equipment by using USB or 10 base –T Ethernet connections.

The devices used by businesses may combine network routers network switches or other networking equipments

DSL EQUIPMENT:DSLAM It really allows DSL to happen

It takes connection from many customers and aggregates them on to a single high capacity connection to the internet It is flexible and able to support multiple types of DSL in a single central office.

DSLAM

LIMITATIONS IT IS A DISTANCE SENSITIVE TECHNOLOGY.

LIMIT FOR ADSL service is 18000 feet.

Maximum downstream speed is 8 mbps at a distance of about 6000 feet.

Maximum upstream speed is 640 kbps.

ADSL cant be received using bridge tapes , fiber optic cables and loading coils. .

INSTALLATION ISSUES

DSL ADSL It do not uses the

frequency spectrum Splitter or micro filter

are used near demarcation point

This requires a technician for installation purposes

More costlier DSL signal is

separated at demarcation point

It uses the frequency spectrum

Frequency filters are used at the customers premises to avoid interference

This do not require technician

Less costlier than DSL DSL signal is filtered at each

phone outlet by use of LPF for voice and HPF for data

ADSL RANGE Maximum range for DSL without a repeater is 5.5 km

As distance decreases towards the telephone company office , the data rate increases

For larger distances , DSL service is provided only when phone company has extended the local loop with optical fiber cable

ADSL SPEED FACTORS The distance from local exchange

The type and thickness of wires used

The number and type of joins in the wire

The proximity of the wire to other wires carrying ADSL ,ISDN and other non voice signals

The proximity of the wires to radio transmitters

ADSL REQUIREMENTS

Phone line , activation by your phone company for it

Filter to separate the phone signal from the internet signal

ADSL modem Subscription with an ISP supporting ADSL

APPLICATION1.HIGH SPEED INTERNET ACCESS

2. E-COMMERCE

3.DISTANCE LEARNING

4.VIDEO CONFERENCING

5.ENTERTAINTMENT-ONLINE GAMING

CONCLUSION

IT IS ASYMMRTRIC.

ALLOWS MORE BANDWIDTH FOR DOWNSTREAM THAN UPSREAM DATA FLOW.

ADSL modems create multiple channels using FDM or echo cancellation.

It is ideal for those who download much more data than they send.

QUERIES ????