Chapter 1 Introduction to Digital Electronic Switch OCB-283 (R24)

Meaning of OCB-283O: Organ C: Control B: Bharsion (Version B) 2: 2nd generation 83: Alcatel microprocessor 8300.

Introduction:OCB 283 is digital switching system which supports a variety of communication need like basic

telephony, ISDN, interface to mobile communication, data communication etc, This system has been developed by CIT ALCATEL of France and therefore has many similarities to its predecessor E-10 B [also known as OCB 181 in France]. The language of OCB-283 is CHILL

The first OCB283 exchanges R11 version were commissioned in Brest [France]. And Beijing [China] in 1991.The first OCB 283 came India in 1993.Subsequently, the system has been upgraded and current version is R24 which was fully validated in January 2003.The exchange which are now being working in the BSNL/MTNL telecom network are of R24 version. R25 version is under development and soon will be validated

Salient features of the system (Including R24)

1. It is a digital switching system with single ’T’ stage switch. A maximum of 2048 PCMs can be connected.

2. It supports both analogue and digital subscribers.3. The system supports all the existing signaling systems decadic, MFR2, CAS and CCS#7 signaling

system.4. It provides telephony, ISDN, Data, communication cellular radio and other value added services5. The system has ‘automatic recovery ‘ feature. When a serious fault occurs in a control unit, it

gives a message to SMM [O&M unit]. The SMM puts this unit out of service, loads the software of this unit in a back up unit and brings it into service. Diagnostic programmes are run on the faulty unit and the diagnostic is printed on a terminal.

6 OCB 283 has a double remoting facility subscribers access unit CSND can be placed at a remote place & connected to the main exchange, through PCM link. Further, line concentrators can also be placed at a remote location & Connected to the CSNL or CSND through PCMS. This special feature can meet entire range of necessities viz. urb semi urban and rural.

7 Various units of OCB 283 system are connected over token rings (IEE 802.5 Standard]. This enables fast exchange of information and avoids complicated links and wiring between various units.

8. The charge accounts of subscribers are automatically saved in the disk, once in a day. This avoids loss of revenue in case of total power supply/ bty failures.

9 The traffic handling capacity of the system is huge .It can handle 8,00.000BHCA And 25000 Erlangs of traffic. Depending on the traffic, a maximum of 2,00,000 subscribers or 60,000 ccts [or trade off between these two] can be connected.

10. The exchange can be managed either, locally or from an NMC through 64 KB/S link.11. All the control units are implemented on the same type of hardware. This is called a station.

Depending on the requirement of processing capacity, software of either one or several control units can be located on the same station. For all these control unit, only one back up station is provided, enabling automatic recovery in case of fault.

12. The OCB 283 system is made up of only 35 types of cards. This excludes the cards required for CSN. Because of this, the numbers of spare cards, to be kept for maintenance, are drastically reduced.

13. The system has modular structure. The expansion can be very easily carried out by adding necessary hardware & software.

14. The SMMs [O&M units ]are duplicated .with one active other hot standby in case of faults, switch over take place automatically. Moreover, as discs are connected to both SMMs, there is no necessity of changing cables from one system to another.

15. The hard disk is very small in size, compact maintenance free .it has huge memory capacity of 12 Giga bytes. The detail billing data are regularly saved in the disk itself, from where they can be transferred to magnetic tape for processing.

16. The space requirement is very small. No separate room is required for OMC.17. There is no fixed or rigid rack and suit configuration in the system. It provides great flexibility and

adjustment in the available space.18. The environment requirements of the system are very flexible. False floor and ceiling are not

essential. Air-conditioning requirement are also not stringent. The system can work at temperatures 5 ‘to 45.’C. though optimum temperatures is 22’C.

19. New subscriber facilities are added in R24 like Centrex and anonymous call rejection and announcement before dial tone.

20. Call filtering and call gaping facility is there.

The next generation switch from Alcatel is 1000 MM E10

The objectives of Alcatel 1000 MM E10 are Multi processor station for call control (up to 8M BHCA) ATM Matrix (16384 PCMs) UMTS Transcoder ATM inter working unit PCM over SDH-STM1 interface Echo canceller in pool With software reuse (E10-OCB-283) services) Unix servers New packaging NGN compatibility (ATM) Ready for MGC evolution (IP)

Capacity of Alcatel 1000 MM E10 BHCA 8 Million Traffic > 200,000 Erlang NB termination up to 16,384 PCM BB termination up to 256 STM1 Subscribers 255,000 Currently (Target > 500,000)

Operation & Maintenance Units and Peripherals.

In an Electronic Stored Program Control Digital Exchange like OCB 283, all operation and maintenance activities are performed by a unit called O&M unit or OMC [operation & maintenance center]. This provides access for man machine dialogues for the human operators to interact and command the working of exchange equipment.

System Architecture

An OCB 283 exchange comprises following hardware units.

1. Subscriber Access units [CSNL, CSND, CSED]2. Trunks and junction connection units. [SMT]3. Switching matrix [SMX]4. Auxiliary equipments [SMA].5. Control units [SMC].6. Time base generator [STS}7. Operation & mtce unit [SMM]8. Communication multiplexes [MIS & MAS Token rings],

Contents of Logical Disks

DL0 Configuration File +CS BOARD, BOOT, EXEC.DL1 RTOS Software SMMA.DL2 RTOS Software SMMB.DL8 SSOM Software SMMA.DL9 SSOM Software SMMB.DL10 AES /SOP.DL11 LOCAVAR Software SSM.DL24 CTILAS-CTI PRMDL25 SMMFIL-DATA, YFDT (220Mb), YOFA (50Mb).DL27 Import/ Export Transfer File. (DGMA area=4239blocks i.e.

8.28 Mb)DL28 Other Application.DL31 PMO.

Fig.1 General Architecture of OCB -283. The subscriber connection units CSN, SMTs, & SMAs are connected to switching network through PCM links.The interchange of messages between SMT, SMX; SMA and control units SMCs takes place on MAS token rings. The control units interchange messages with one another and with SMM on MIS token rings.

The SMM is the O&M function unit &is duplicated as SMMA & SMMB. These work in pilot/standby mode.The SMCs are the units which hold control functions MR, TX, MQ, PC, GX, These functional units are in software form and are duplicated except MR which can be more than two. The duplicated functions work in Load sharing mode [except PC which works in pilot/standby mode] hence SMCs can be minimum 2 & maximum 32 as per design. The SMA stations hold the ETA & PURE functions &these are also minimum 2 to maxi.32.SMT station which is the interface for the external PCMs is made of duplicated hardware and can handle 128 PCMs . The SMT’s hardware is fully duplicated and functions P/R mode.

Block diagram of OCB-283

M A MAS RING L

MIS RING

CV

PCWAM

Console

SMX

SMT

CSNL

CSND

STS

SMA

SMC SMC SMC

SMM

CNE

The brief description of these units is as follows. Switching NetworkThe switching network in OCB 283 is single ‘T’ Stage system. It is made of

o Host switching Matrixo Branch selection amplification [SAB] function

Host switching matrix consists of two identical branches A & B. The host-switching Matrix is implemented on the hardware units known Matrix Control stations [SMX]. Each host-switching matrix can have up to 2048 incoming PCM links [LRE] and 256 outgoing links LRS. Out of 2048 incoming links only 256 link are directly coming from this Matrix control station. The remaining links are coming from the other seven SMXs. In full configuration, the host-switching matrix is 2048 x 2048 matrix. This illustrated in fig.5 .A matrix control station can establish connection between any TS on 2048 LRE to any TS on 256 LRS. Similarly, almost switching matrix can establish connection between any TS on 2048 LRE and any TS on 2048 LRS. Three standby configurations with 256 LRs, 1024 LRs and 2048 LRs are available. The Matrix control station is built around a processor, which implements sw machine. MLCOM functions, to establish & break connections between time slots. It also carries out two-way communication with other units in the system over MAS rings.

Time Switch ConceptThe time switch comprises of A SPEECH BUFFER MEMORY, A CONTROL MEMORY, AN INCIMING HIGHWAY OF DIGITAL SPEECH IN PARALLEL BITS & AN OUTGOING HIGHWAY as shown in the diagram below. This is a INPUT ASSOCIATED CONTROLLED TIME SWITCH. In this switch the BUFFER MEMORY & CONTROL MEMORY are controlled write type i.e. writing in it is controlled. The control function writes in the control memory at the location corresponding to the INCOMING TIME SLOT NUMBER the location where it should be written in the Buffer memory. Both these memories are sequential read type. Reading of control memory gives the address in Buffer Memory for writing the INCOMING TS BYTE. And thus reading of Buffer memory sequentially the TS will be read from the location given by the control memory. Thus a one-way TIME switching has taken place. Similarly a both way switching requires two sets of such switches. Duplicated Switching The switching is done in OCB-293 in two fully duplicated branches simultaneously. For this purpose from each connection units the LR links originate in two parallel branches towards two parallel sets of switching matrices called SMX A & SMXD the branches of such network are called A&B branches. Also the receive side LR links come from both the SMXs A&B and are terminated on the respective connection units.[refer to as UR in figure below].The duplicated branches of switching have been designed to provide high reliability of switching path for such divers purposes as DATA SWITCHING ,VIDEO CONFERENCE ,ISDN APPLICATIONS etc. With the duplicated path of switching if their error in on path the other path that is good can be used continuously without interrupting the call in progress.

SAB Function.The connection units have their internal duplicated hardware, which is called CONTROL LOGIC, which work in PILOT/RESERVE arrangement. also they have non duplicated hard wares such as subscriber cards and PCM termination cards. The duplicated LRs originate from a function in connection units called SAB-Selection and amplification of branches. Its role is to generate two sets of LRs in trans direction with calculation of parity etc. In receive direction it gets data from both the branches, which it checks, for parity etc. And compares to detect any error in the two branches. In case of error the samples from only the good branch are taken after automatic testing of the quality of transmission of both the branches by the common control & the faulty branch is withdrawn from the service. The connection units ‘LR links are foamed

1. Subscriber Access Units [CSN]

Subscriber connection units [CSN] are so designed that they can be equipped with either analogue or digital subscriber or both. The card for analogue and digital subscriber are different, but can be equipped in any slot. of the shelf CSN can be either placed in the exchange switch room or at a remote location. Further, subscriber card shelf known as concentrator can also be placed at the rack or at a remote location. These features provide great flexibility to meet any type of requirement of dense or sparse connection densities. Depending on their location, CSN is known as CSNL or CSND and the subscriber shelf is known as local or remote concentrator. CNL or CNE

The CSNL is connected to switching matrix [SMX] through a minimum of 1 GLR or a maximum of 2 GLRs. [Group of 8 LR is called as a GLR and each LR is a PCM link having 32 time slots]The CSND is connected to SMT rack through a minimum of 2 PCM and maximum of 16 PCMs

CSED of E-10B system can also be connected to an SMT.

Out of 48 LRIs a maximum of 42 LRIs can be used to connect concentration to SMX.42 for CN from 6 to 47 3 for GTA from 2 to 4 2 for TCCS from 0 and 1 1 not used 5

Total 48 LRIsMaximum 19 CSL and maximum 20 CNEs ICNE allows 42 PCMs for 20 CNEGTA is always concentrator number 20 i.e. GTA= CN20.

Dialogue with CSN: -The massage interchanges between CSN and control units take place on common signaling channel using local version of CCS#7 SIGNALLING. The CSN is so designed that it can be connected to any switch supporting CCS# 7.

2. Trunk and Junction Connection Unit [SMT]

General Architecture of SMTThis is also known as PCM trunk control station. This unit is an inter face between PCM junction coming from other exchange [for CSND, CSEDs and the switch. The current version of SMT being supplied to India is SMT 2 G

In each SMT 2G, there are 8 modules and in each module there are 16 PCMs. Thus there are 128 PCMs, in a single SMT 2G. SMT 2G is built around microprocessor 68030

SMT 2G consists of duplicated processing subsystem. SMT A and SMT B, which are connected through internal link LISM. Both of them are connected to PCM inter face as well as to MAS token rings. PCMs are connected to PCM interfaces, which, are not duplicated. SMT 2G is connected to SMX A and SMX B through 128 PCMs, which are connected to SAB branch A, and SAB branch B.Speech samples are sent on both the branches from SMX, but one, which is better, is selected and connected to the concerned PCM TS by SMT. The SAB Function [branch selection and amplification] is also not duplicated. Out of the two processing logics, SMT A and SMT B, one remains active and other standby. In case of fault in active logic, automatic switch over takes place providing an uninterrupted service. Also LOCAVAR is activated on the faulty logic and the diagnostic is printed on a terminal for the information of the maintenance staff.

PCM is through

Internal loop & external break

Both side loop

Internal break & external loop

ICTRQ

SMT-A

221 219 217

0 4 8 12

1 5 9 13

2 6 10 143 7 11 15

223

SMT-B

222 220 218 216

FunctionsThe software MLURM is loaded on SMT to perform functions of a PCM controller.

The functions performed on receive side-o Converts HDB3code to binary.o Extracts channel associated signaling.o Manages CCS 7 message carried on TS 16.o Cross-connects a channel on PCM to a TS

on LR

The functions performed on transmit side-o Converts binary code to HDB-3 [line] code.o Injects channel associated signaling.o Massage CCS 7 massage on TS 16.o Cross-connects a TS on LR to channel on

PCM

3. Switching matrix [SMX]

Switching Matrix System (CCX)Role of the CCX:The switching Matrix system establishes interconnections of time-domain channels for local subscribers digital access units (CSNLs) and the Trunk Control and auxiliary equipment control stations:

In general the switching Matrix System carries out: -

o Unidirectional connection between any incoming channel (VE) and any outgoing channel (VS). There can be as many simultaneous connections as there are outgoing channels,

o Connection between any incoming channel and any M outgoing channels.o Connection of N incoming channels belonging to the same frame structure of any multiplex to N

outgoing channels, which belong to the same frame structure, abiding by the integrity and the sequencing of the frame, received. This function is referred to as “ N x 64 Kbit/s connection “.

A bi-directional connection between an A end (calling party) and a B end (called party) takes place in the form of two unidirectional connections.

The switching Matrix System thus ensures:

o Switching between auxiliary equipment and speech channels for voice frequency signaling operations

o Simultaneous distribution of tones and recorded announcements to more than one outgoing channels.o Permanent switching of channels, which support data links or semaphore links between circuit and

circuit or between circuit and auxiliary equipment control Station.

Switching Matrix System organization (CCX)

The Switching Matrix System pools:- The Host switching Matrix:

16 bit switching, including 3 reserved. Matrix of 2048 x 2048 matrix links with one time –domain stage, 64 matrix links equipment modularity,

- The Branch Selection function: Selection, Amplification, Interface of connection stations (CSNL, SMT, SMA.) Time distribution interface,

- Matrix links: 4 Mbit/s rate, 8-matrix links connection modularity.

All duplicated (branch concept)

Operation of Switching Matrix System: Connections are established in both branches. Selection of the active branch for a Time slot (TS) is carried out by comparing the outgoing time

slots of each branch

Supervision of the unit is carried out by the connections management software machine (Matrix System Handler GX).

Host Switching Matrix (MCX)The Host Switching Matrix is made up of two branches, A and B, and from the hardware point of View, is made up of Matrix Control Stations(SMX). A branch of the Host switching Matrix contains from 1 to 8 Matrix control Stations. Each Matrix Control Station receives a tripled time base signals (8 MHz and frame Synchronization) coming from STS and following majority choice distributes information to the exchange and to the Matrix link Interfaces (ILR).

Each Matrix Control Station handles 256 incoming matrix links and 256 outgoing matrix Links within its network liaison interfaces (ILR). On output from the incoming side ILR, The LCXE links of homologous numbers are multiplied on the same position of all the Matrix Control Stations. Each time-domain matrix is capable of handling the switching any time slot of the 2048 incoming matrix links, to any timeslot of its 256 outgoing Matrix links. Matrix Control Station (SMX)

Each SMX includeso A Multiplex Coupler (CMP), which permits two-way communication on MAS ring and performs

the “processor” function for the Matrix Switch Controller Software Machine (ML COM).o A coupler to the time domain matrix,o Matrix Link Interfaces (ILR) for a maximum of 256 incoming matrix links and 256 outgoing

matrix links,o A time-domain matrix of maximum capacity of 2048 incoming matrix links and 256 outgoing

matrix links.

There are 3 types of board:- Main Multiples Coupler (CMP ACAJA, ACAJB) - Matrix Coupler RCMP

4. Auxiliary Equipments Control Station [SMA]

The SMA contains following two functional units (1) ETA & (2) PUPE

ETAThe ETA contains following sub components

a. Frequency receiver/generatorsb. Conference call circuitsc. Tone generators

The frequency receivers / generators recognizes the digits dialed through DTMF instrument & also the MF (R2) signals received on junctions. They also generate the various frequencies required for MF (R2) signaling and testing etc.

The conference ccts are used to set up connection between a maximum of 4 subscribersThese 4 subscribers can holds conference on the telephone i.e they can talk to each other. Tone generators generate various tones required to be connected during call processing. These tones are dial tone, Busy tone, ring back tone, processing tone etc.

PUPE

The PUPE performs level 2 and part of level 3-function s for CCITT no.7 signaling. The rest of the level 3 functions performed by PC. The arrears the various functions performed by PUPE are as below.

Transmit side1.) It sends ‘flag’ and ‘check bit’ in the HDLC frame while transmitting CCS7 messages. It also inserts zeros, when there are more than 5 consecutive ones (1S) in the message.2.) PUPE sends ‘fill in signal units ‘ (FISU) automatically, when there are no messages to be sent.3.) PUPE also sends ‘link status signal units’ (LISU) when commanded..4.) It re-transmits a signal unit on receipt of negative acknowledgement.

Receive side1) On receipt of CCS7 signaling messages ,it eliminates zeros which were inserted

after five consecutive Ones (1S) .

2) It detects the flag and also computes the checksum and compares them with check bits. If these two match , it sends positive acknowledgement otherwise it sends a negative acknowledgement.

3) It eliminates’ fill in signal units’ as they do not carry any information.

Implementation of ETA and PUPE on SMA

Either ETA or PUPE or both can be implemented on the same SMA. When both are implemented on the same SMA, MLPUPE (Logic machine PUPE i.e. PUPE software) is loaded on the principal processor (PUP) and MLETA is loaded on secondary processor (PUS)When only PUPE is implemented on SMA, it is loaded on PUP and when only ETA is implemented, it is loaded on PUS.Only first two ETAs have tone generators. CCFs and RGFs are provided as per requirements. The PCB used is common for RGF, CCF and Tone generators, only the software is different. When no CCF or tone generator is required, an ETA can have a maximum of 96 RGFs.An SMA is connected to SMX by 8 LR links. The following table illustrates the capacity & modularity of SMA.

SMA Units equipped with Capacity Min & Max No.ETA alone 96 RGF 2 to 32PUPE alone 64 CCS 7 Channels 2 to 15ETA & PURE both 64 RGFs/32 CCS 7 Channels 2 to 15

5. Station control unit (SMC)

Since all the control units like MR, MQ, TX, TR, etc and SMA are implemented on a common type of hardware architecture, known as station, it is worthwhile to understand the architecture and concepts of stations.A station is built around a multi processor station bus ‘BSM’ .One or more processor and one or more intelligent couplers can be connected to this bus. They interchange data through the common memory. The principal or main processor is connected to common memory through a 32 bit private bus, apart from through BSM. All the processors are Motorola 68020 processors and operate at 15.6 MHz. clock. Multi processor station bus BSM is a 16-bit bus, which operates at 44.8 Mbs. A block schematic of a station is shown in the figure 5. There can be one principal processor (PUP) and 4 secondary processors (PUS) in a station. Similarly, there can be main coupler (CMP) and up to 4 secondary couplers (CMS). Specific couplers can be equipped for specific purposes. A station can function as MR, TR or any other unit than particular software is loaded in the station. Depending on traffic and processing requirements, software of either one or several functional units can be loaded in the same station. Also, depending on the above requirements, a functional unit can be implemented on principal or secondary processor and on main or secondary coupler.

To permit co-habitation of many software machines on the same station, basic software known as hyper visor is provided on the station. Another software, known as supervisor provides communications and loading facilities.The station is generally known as SMC.

Implementation of control functions on SMC stationsThere are six common control functions in a OCB-283 the following list illustrates their minimum and maximum numbers.

S.No. Name of Unit Minimum Maximum1 MR 2 72 TR 2 2

3 TX 2 24 MQ 2 25 PC 2 26 GX 2 2

They are known as LOGICAL MACHINES in software form. These logical machines ‘ML’ are implemented on the hardware of SMC (Station) by loading suitable software on it. An SMC can support any one or many MLs or functions in defined combinations.

Accordingly depending upon exchange configurations & traffic requirement there can be minimum TWO SMCs required & maximum number of SMC can be 32 but no more than 15 are needed. The required number of SMCs is decided by planners & manufacturers based upon traffic data. In addition to this , there is a provision of one ‘back up SMC station’. This back up station is not loaded with any software.

Whenever, any SMC becomes faulty, it sends message to SMM .The SMM blocks this unit and informs all control units regarding non-availability of this unit. SMM then loads the software of all the functional units on the back up stations and brings it into service. Thus, there is automatic recovery. SMM also runs diagnostic program on the faulty station and puts diagnostics on a terminal.

Fig SMC Station Configurations

Functional configuration and general organization of control software

According to the number of equipped SMC the ocb-283 switching exchange is standardized through 8 possible configurations as per following table.

Configuration R23/R24 Capacity in CA/s (Call attempt per sec.)

P1 2 SMC 48P2 3 SMC 48M1 5 SMC 96M3 7 SMC 144G1 9 SMC 192G2 10 SMC 240G3 13 SMC 288G4 14 SMC 336

Calculation of BHCA

For 7 SMC Configuration Call Attempt Per Second Is 144 Multiply this with 3600,which will give you BHCA

i.e BHCA=144 x 3600 = 518400

Rated traffic=Capacity * 0.7/2 +10% of previous calculation

Configuration is chosen on the basis of Processing power to be offered in CA/s Number of calls supervision contexts required (Processed by MR) Number of call charging contexts required (Processed by TX)

Functions of various common control software of SMC

Functional Software machines MLMR Call handler SETUP & RELEASE OF CALLS MLTR Translation of digit Databank of subs & circuits in files. MLTX Call charging and circuit/subscriber observation MLMQ distribution of messages between common control & communication. Units. MLGX Processes& make connections in switching matrix on the orders from MR or MQ. MLPC CCS#7 network controller MLCC Call controller (setup and release of call with mobile subscriber) MLGS Server management (mobile subscriber only). MLAN Access Network interface software for V5.2

1. Multi register (MLMR)The MR establishes and realizes the calls .It talks real time decisions for processing of a call. The MR also consults TR to find out subscribers entitlements and stores digits dialed by subscriber. It also orders for connections and disconnections of various tones and subscribers. In addition to call processing functions, MR also carries out testing, of ccts and observation functions.

Recognizing subscriber off hook and on hook conditions or circuit seizures. Receiving, storing and analyzing the dialing information from a subscriber or circuit. Forwarding the dialing information. Controlling in the host-switching matrix. Connections and disconnections.

Controlling transmission of various signals and tones. Communications with MLTR Communication with MLTX.

2. Translator (MLTR)The TR stores exchange database in its memory .On request, it tells MR the characteristics and entitlements of subscribers and ccts.The TR also stores routine and analysis data. It converts (or translates) the received digits into equipments number of the called subscribers.

3. Charging unit (MLTX)As the name suggests, the TX carries out charging for each communications set up. Also keeps charge accounts of all subscribers. The TX also prepares and sends details billing messages to SMM. In addition, it also carries out subscribers and ccts observation functions.

4. Marker (MLMQ)The marker carries out messages between common control functions MLs and connection units for subscribers or ccts. It also acts as ‘gate’ for messages, which pass from one communication domain to another. The MQ also supervises semi permanent connections in the net works.

5. Matrix systems handler (MLGX) The GX monitors the connections in the switching network and in case of fault, carries out appropriate defence functions. It also periodically or on request monitors internal links in the switching network.

6. CCS7 controller (MLPC) The PC carries out ‘ routine & traffic’ management functions (part of level 3 functions) for CCITT No.7 signaling. It also carries out the defence of PUPE, i.e. if a PUPE develops fault, it is automatically blocked, the semi permanent link is reconfigured and the standby PUPE it brought in service. The PC also carries out observation functions.

7. MLCC (Call controller software machine)

MLCC plays an important role in call handling for radio telephone access.MLCC is made up of-

- a main component - 1. System functions.- Calling, time delays, contexts and initialization.- Message preprocessing.- System processed: routing, regulation, debugging, defence.- 2.. application processes.- Main positioning.- Observation.- Operation/ maintenance block.- Management.- A secondary component capable of being n- plicated on n agents and having the same

structure as the main component.

General organization of control software

More precisely a control station supports the following software subsets An operating system the HYPERVISOR which controls access to hardware, allocation of

resources to software, communication between stations etc. A variable number of software package called software machine (ML) of two types.

1. One or more software machines called functional or application MLs each handling a telephone function of the system.

2. A software machine called MLSM controlling station operation i.e. communication, loading, initialization, defence etc.

The HYPERVISOR & MLSM installed on all control station form the station’s SYSTEM SOFTWARE. However a given functional ML is installed according to the configuration requirements.

HypervisorThe HYPERVISOR is the station’s operating system. As well as allowing each ML to be independent of its physical location, is also enables MLs with different function, to co-exist on the same processor or on several processors of the same SM.

It offers the following services. Time management Communication Timers Access to files Interrupt’s handling Observation (time consumed by ML)

Functional Software machines MLMR/ TR/ TX/ MQ/ GX/ PC/ CC/ GS

Component of a functional MLIt can consist of one or more execution units called COMPONENTS and installed on different active agents.

A component is therefore a subset of a ML running on al particular processor. A component executes a sequence of individual actions, each action activating a service. These services are placed in sequence by the SEPERVISOR forming the operation system of the component.

Supervisor provides.

Activation or deactivation of service. Standard services available to application: periodic task management Processes handler Management of returned hypervisor mode Time and event counting for load observation purposes.

MLSMMain component installed on the main multiplex coupler CMP of the stationSecondary component installed on each of the active agents of the station (PUP, PUS)

Main component MLSM handles loading and initialization of the MLSM and of the functional software machines, positioning of the station, updating of status files, local defence and control of observation functions and acts as debugging aid.

Secondary components handles loading and initialization of the agent, its defence and observation functions.

MLSM offers the functional MLs declaration, software positioning and software fault processing functions.

6. Time base Generator [STS]

Role of Synchronization and Time Base Station

The Synchronization and Time Base Station incorporates 3 functions: External Synchronization Interface (HIS) clocks Tripled Time Base (BTT) Alarms.

Synchronization and Time Base Station ArchitectureThe Synchronization and Time Base Station includes:

A Tripled Synchronizations Time Base (BTT) and is made-up of three RCHOR boards and distributes the time signals necessary to the Connection Network Stations of the ALCATEL E 10B OCB 283 system like SMX, SMA, SMC etc.

An External Synchronization Interface (HIS) and made up of RCHIS boards and which can be duplicated (0 to 2 boards) and extracts clocks retrieved from PCMs coming from SMT. The Synchronization unit can receive 4 PCM clock.

PCM designated for external synchronization are

AMET=223-1-4 LSR0AMET=223-2-4 LSR1AMET=223-3-4 LSR2AMET=223-4-4 LSR3LSR, which is blinking, indicates the external synchronization link used to synchronize the RCHIS board

RCHIS board must be taken out when V1 switch is down and can be inserted when V1 switch in center position.

RCHIS board takes 24 hours to stabilize and if an external sync fault occurs during this period the stabilization process starts again.

Connector wiring for external synchronization (rear side of rack)

Left Side Right Side1st pin is to be Earth Wire. 1st pin (IN OF WTR) IF RED WIRE.2nd & 4th pin are to be LOOP. 3rd pin (OUT OF WTR) IF BLUE WIRE.

Single Pair Cable should be used for wiring to connector. Plug in both Connector on slot 84 and 110 on rear side. Then Remove RCHIS Card of slot 110 by keeping V1 switch down and keep it out Reset the RCHIS Card of slot 84. Wait for five to six hours for synchronization. LX Lamp of card slot 84 is blinking. Whereas

others L0, L1, L2, L3 are remaining steady. At this time the Status is now D4 LAMP is Green and after synchronization D3 LAMP will be

GREEN of slot 84. Now insert RCHIS card of slot 110 and reset it. Wait For 5 to 6 hours. The final status of lamp

will be LX Lamp blinks whereas others L0, L1, L2, L3 are steady.

.

RCHIS board

ON : HIS alarm : HIS ALARM BLINKING : HIS alarm by taking out of service

Manually or for minor fault

ON: No External Synchronization

ON: Synchronization on LSRx ON: Synchronization on LSRi D3/D4 Blinking: External calibration

Momentarily Up : Reset Middle : Normal OperationDown : Manually Disabled

ON: Quick locking state

ON: LSRX input Operational

ON: LSR3 input Operational AMET= 1-4-4

ON: LSR2 input Operational AMET= 1-3-4

ON: LSR1 input Operational AMET= 1-2-4

ON: LSR0 input Operational AMET= 1-1-4

o D1

o D2

o D3

o D4

o V1

AR

LX

L3 L2 L1 L0

Features in R25 software version of OCB-283

CLI dependent routing on a specified trunk group (CCS#7 signaling): This feature is used to choose a route based on the CLI (digit) received

Routing based on “calling line category” (CCS#7 signaling): The routing of the calls at Tandem and TAX are decided on the basis of subscriber category received through signaling.

Carrier Pre-selection. Announcement to calling subscriber, making a call to subscriber in call waiting. Announcement on registration of password or change of password (in place of

acceptance tone). Variable ringing duration for call forwarding on No-Reply per subscriber basis: Any

subscriber whose line has the “call forwarding on no-reply” supplementary service. It is possible to choose “no-reply timeout”. Subscriber can modify the “no-reply timeout” by using a separate access code followed by the duration in seconds.

CDR for terminating calls Call forwarding to fixed number and MWI (Message Waiting Indication): This facility

can be used by subscriber to forward the calls to a voice mail service. The forwarding number, which is fixed in this case, can only be changed through operator commands. Subscriber can only activate or deactivate this facility.

Suppression of A5 after A4.

Now above features are briefly described as follows.1. CLI dependent routing.

Here TYPE=20 routing is used@ACHCR:@ACH=xx, TYPE=20, STY=CLI, ACM=1-[TRAD-1]+[ACHx]-[TRAD]+1-[TRAD+1]<16;

@PRECR:@PREA=10, PRE=xx, TRAD=yy, RCE=1, RCA=1;

@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=33,NOMS=XR052X,CHSI=PREALI-10,AF=ALL;ARCH=XATR,FICH=FIPAM,NUM=69,NOMS=XR052X,CHSI=MXIDR-15,AF=ALL;ARCH=XATR,FICH=FIOIDR,NUME=0,NUMA=2,CHSI=ZDR1-1,AF=ALL;ARCH=XATR,FICH=FIOIDR,NUME=0,NUMA=3,CHSI=ZDR1-2,AF=ALL;ARCH=XATR,FICH=FIOIDR,NUME=6,NUMA=2,CHSI=ZDR1-1,AF=ALL;ARCH=XATR,FICH=FIOIDR,NUME=6,NUMA=3,CHSI=ZDR1-2,AF=ALL;

2. CLC dependent routingHere TYPE=20 routing is used@ACHCR:@ACH=xx, TYPE=20, STY=CATDR, ACM=1-1<[index-1]+[ACHx]-[index]+1-[index+1]<255;

Where index=[operator category]+1

@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=43,NOMS=XRA527,CHSI=MXCDR-254,AF=ALL;

@ARCIN:

ARCH=XATR,FICH=FIAF,NUM=1221,FORM=AUT;ARCH=XATR,FICH=FIOCDR,NUM=<internal category>,FORM=EDN;

3. Variable ringing timer for call forwarding on no reply

@ACHCR:@ACH=Ax, TYPE=16, CAR=TYFA006+TYPU011;

Here TYPU=4 (Check), 5(Enable), 6(Disable), 11 (Modify timer)

@INDCR:IND=xxx, TRAD=3, ACHN=Ax-,….@ABOMO:ND=xx, CAT=RVFT+RVFO+RFNR,…

4. Fixed forwarding and MWI (Message Waiting Indication)

To play announcement

@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=39,NOMS=XRA523,CHSI=TFLADM-<film No.>,AF=ALL;

Announcement duration@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=37,NOMS=XRA521,CHSI=TARAC-<sec..>,AF=ALL;

5. Carrier PreselectionThere are four methods of carrier sections.

a. Per call basis by dialing access code and carrier code.b. Carrier preselection by category assignment to the subscriber.c. Carrier selection by default carrier declaration.d. Transit Network Selection (TNS)

@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=60,NOMS=XRA520,CHSI=PRET-11,AF=ALL;ARCH=XATR,FICH=FIPAM,NUM=52,NOMS=XRA52G,CHSI=NBSTR-2,AF=ALL;ARCH=XATR,FICH=FIPAM,NUM=52,NOMS=XRA52G,CHSI=NT9-2,AF=ALL;ARCH=XATR,FICH=FIPAM,NUM=50,NOMS=XRA52E,CHSI=NTRA09-9,AF=ALL;ARCH=XATR,FICH=FIPAM,NUM=38,NOMS=XRA522,CHSI=NARM-1,AF=ALL;

For default carrier code (45) declaration.@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=52,NOMS=XRA52G,CHSI=TRDA4-5+TRDA3-4,AF=ALL;

6. Announcement for SRC facility acceptance@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=34,NOMS=XR052Y,CHSI=VFA-1,AF=ALL;

@RNVMO:RNV=95, ACHB=<announcement No.>;

7. Announcement to call waiting

Announcement for 30 seconds@ARCMO:ARCH=XATR,FICH=FIPAM,NUM=39,NOMS=XRA523,CHSI=TFLIAI-<film no.>,AF=ALL;

Announcement if second call is not answered within 30 seconds. @ARCMO:ARCH=XATR,FICH=FIPAM,NUM=60,NOMS=XRA520,CHSI=TFLIAI-<film no.>,AF=ALL;

8. CDR for termination calls

@ABOMO:ND=xx, CAT=DEA;