INDEX

ABOUT BSNL CDMA SYSTEM EQUIPMENTS AND CABLING SYSTEM USED TYPES OF EXCHANGES AND SWITCHING NETWORKS COMPUTER DIVISION OF BSNL SERVICES PROVIDED BY BSNL GOALS AND RESONSIBLITIES OF BSNL

About BSNL - Bsnl is a govt of India enterprise and the dominant service provider of fixed line services throughout India (except for Mumbai and New Delhi). Bsnl has been

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given he license by the govt of India, for providing cellular services for the entire country. as on date, Bsnl has over 34 million fixed line subscribers. It has grown its subscriber base by over 5 million in the last one year. Its vision is to be a high tech customer oriented company with emphasis on value addition and to provide seamless country services.

VISION - BSNL would like to be a high-tech customer oriented company with emphasis on value addition.

MISSION - To provide world class telecom services on demand using state of technology for our valued customers at affordable price.

TRAINING CENTRES

Bsnl has basically three types of training centers, which are as follows1) ALTTC( ADVANCED LEVEL TELECOM TRAINING CENTRE)2) RTTC (REGIONAL TELECOM TRAINING CENTRE)3) CTTC (CIRCUIT TELECOM TRAINING CENTER)

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CDMA SYSTEM

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Architecture of CDMA system

Um E

Abis A

Q C

B

N N

MS

BTS BSC

PSTNMSC

MS C/SSP VLR

HLR AUCMC

D

MCM

MSS

BSS

Ai

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•MS: Mobile Station

•BSC: Base Station Controller

•BTS: Base Transceiver Station

•MSC: Mobile Switching Center

•VLR: Visitor Location Register

•HLR: Home Location Register

•AUC: Authentication Center

•OMC: Operation and Maintenance Center

•MC: Message Center

Architecture of CDMA system

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1 Main components of CDMA

MSS (Mobile Switching Sub-system) BSS (Base Station Sub-system) MS (Mobile Station) OMC (Operation and Maintenance Center)

1.1 Base Station Sub-system

•Function: It provides trunks between wireless part andFixed part of PLMN network.

BSC-BSC performs the controlling function and management.

BTS-BTS is in charge of wireless transmission.

1.2 Mobile Switching Sub-system

•Function:

CDMA switching functionManage mobile subscriber dataManage database for mobile serviceInterface between CDMA network and other network(such as PSTN, other PLMN etc.).

•It includes 4 function units:---MSC ---VLR---HLR ---AUC

1.2.1 Mobile Switching Center (MSC)

•It is responsible for setting up, managing and clearing connectionsas well as routing the calls to the proper user.• It provides the network interfaces, the charging function and theFunction of processing the signaling.• MSC get data for call handling from 3 databases: VLR/HLR/AUC• GMSC (gateway): When a non-CDMA end subscriber calls a

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CDMA subscriber, the call will first be routed to a GMSC.

1.2.2 Visitor Location Register (VLR)

•VLR is a dynamic database used by MSC for information index. ItStores all related information of mobile subscribers that enter itsCoverage area, which enables MSC to set up incoming and outgoingCalls.•Subscriber parameters include: subscriber number, location areaIdentity (LAI), user’s status, services which subscriber can use andso on.•When the subscriber leaves this area, it should register in anotherVLR and the previous VLR will delete all the data about thisSubscriber.• VLR can be built together with the MSC or set separately.

1.2.3 Home Location Register (HLR)

• HLR:It is a static database. When a user apply for mobile service, allData about this subscriber will be stored in HLR.•Information:----Subscriber information (ESN, MDN, IMSI, MIN), serviceInformation and valid term.----The mobile subscriber location (MSC/VLR address), so as to setup the call route to the MS.• HLR can be built together with the MSC or set separately.

1.2.4 Authentication Center

• Conception: It is an entity to prevent illegal subscribersFrom accessing CDMA network. It can generate theParameter to confirm the subscriber’s identity. At thesame time it can encrypt user’s data according to user’sRequest.• Composition:— Database (save MIN, ESN, and authentication key)— Generator of random number— Algorithm (CAVE algorithm)— AUC can be built separately or together with HLR

1.2 Operation and Maintenance Center (OMC)

OMC provides operation and maintenance services to thenetwork operator, manages the registered subscriber informationand conducts network planning to enhance the overall workingefficiency and service quality of the system.Based on the main maintenance functions, there are two types of

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operation and maintenance centers: OMC-S and OMC-R. TheOMC-S is mainly responsible for maintenance of MSS while theOMC-R is mainly for BSS.We also call OMC as background.

wireless Area partition

• CellThe smallest area that can not be divided.

• Location area:The area where MS moves without updating location.It includes some cells.It only belongs to one MSC.It includes one or more BSC.One location area has one LAI to identify each other.

• MSC service area:The area that all the cells controlled by one MSC covered.One MSC composes one or more location areas.

• PLMN service area:It includes one or more MSC service areas.

• CDMA service area:It includes global PLMN networks.

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Interface between different entities

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Interface between different entities

Um E

Abis A

Q C

B

N N

MS

BTS BSC

PSTNMSC

MS C/SSP VLR

HLR AUCMC

D

MCM

MSS

BSS

Ai

The difference between interface and protocol:•The interface:The connection point between two adjacent entities.•The protocol:To illustrate the rules followed when information exchangedat the connection point.

1. Um interface

Um interface defines the communication interface between MS andBTS also called air interface.• It realizes the compatibility between all kinds of MS andDifferent BTS, so that the MS can roaming.(It is an open interface)•It realizes the physical connection between MS and CDMAnetwork.(that is wireless link).

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2. Abis interface•The interface between BTS and BSC, used for remoteConnection.•2.048 Mb/s PCM digital link

3. A interface•It is the interface between BSC and MSC•It is based on 2.048Mb/S PCM digital links•A-Interface is mainly used to transmit the followingInformation:— BSS management information— Call processing— Mobility management•It is an open interface.

4. B interface•The interface between MSC and VLR.• MSC transfer the location information of roamingSubscriber to VLR.• Query subscriber data from VLR when setting up theCalls.• Usually VLR is built with MSC together, so theInterface turns to be an internal interface and has noStandard rules.

5. C interface

•The interface between MSC and HLR.•The interface is based on 2.048Mb/s PCM digital link.•When a MS is called, MSC must query the called MS’sRouting message from HLR through this interface to locate theCalled MS, and according to the record, HLR will return theRouting message (MSC/VLR number) to MSC.

6. D interface•The interface between VLR and HLR.•The interface is based on 2.048Mb/s PCM digital link.•The interface is used for exchange of subscriber locationInformation, authorization information and service data.

7. E interface•The interface between MSC and MSC. It is used for channelChange over between 2 MSC•The interface is based on 2.048Mb/s PCM digital link.

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•When a mobile station roams from one MSC to another during theSpeaking, the MSC will perform handover to keep the subscribers'Conversation uninterrupted. In this case, data exchanging must beImplemented between the MSCs.

8. Q interface•Interface between SC and MSC. .•The interface is based on 2.048Mb/s PCM digital link.•In submission and reception of short messages, short messagesare transferred among the short message centers and the mobileswitching centers. At the same time, when the subscriber's shortmessage capability changes, the mobile switching center shouldnotify the short message center promptly.

9. Ai interface:The interface between MSC and PSTN, used for setting upvoice connection between PSTN and PLMN.

Numbering plan

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1. Mobile Directory Number (MDN)

• An MDN number is the number dialed by the Caller.

• Composition of an MDN number.

CC: Country Code (CC=86 in China )

MAC: Mobile Access Code(China:133)

H0H1H2H3 : to identify different HLR

ABCD: mobile subscriber number

CC MAC H0H1H2H3 ABCD

International MDN

National MDN

+ + +

Numbering plan

2. International Mobile Subscriber Identificationnumber (IMSI)•IMSI can identify a mobile subscriber in the PLMN network.•IMSI is used in signaling in a CDMA network, stored in HLR,VLR and the UIM card.

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•Composition of an IMSI number:MCC + MNC + MSIN•MCC= Mobile Country Code (MCC=460 in China )•MNC= Mobile Network Code (China :03)•MSIN = Mobile Subscriber Identification Number, a 10-bitalgorism number, expressed asXX + HoH1H2H3 + ABCD

XX is allocated by international organization (China:09 or 03)HoH1H2H3 is the same as HoH1H2H3 in the MDN number.ABCD is a subscriber number.

3. Mobile station Identification Number (MIN)MIN is the same as MSIN

4. SID & Switch No.•SID: System Identification.Each mobile local network is assigned with an SID, which isdecided by the headquarter.

•Switch No.:To identify different equipments with the sameSID.8. Location Area Identification number (LAI)•LAI is used to identify the location area.•Its structure is:MCC+MNC+LACMCC and MNC : same as the MCC and MNC in IMSI.LAC is a location area code that uniquely identifies eachlocation area in our digital PLMN. It is a 2-byte hexadecimalBCD code represented by L1L2L3L4 (with the range of0000~FFFF, able to define 65536 different location areas.)•Structure:

MCC+MNC+LACMCC and MNC : same as the MCC and MNC in IMSI.LAC is a location area code that uniquely identifies eachlocation area in our digital PLMN. It is a 2-byte hexadecimalBCD code represented by L1L2L3L4 (with the range of0000~FFFF, able to define 65536 different location areas.)

9.Global Cell Identification (GCI)•It identifies certain cell in a location area.•Structure:MCC+MNC+LAC+CICI:2 bytes hexadecimal BCD code.

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10. Electronic Serial Number (ESN) It is set by the manufacture of the mobile station.

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EQUIPMENTS USED

Connecting mediums:

Various types of cables are used to provide connections to subscribers that are as follows:

1. Open wire cable: these are simple conductor wires used in home.

2. Paper core cable:

There are special types of cables used for connections, which are as follows: PCUT- paper cut unit twin PCQT- paper core quad trunk PCQL- paper core quad local PCQC- paper core quad carrier

3. Jelly filled cable:These are bunch of wires in pairs, and jelly like material is filled in cable.Cables contain nos of pairs, which are arranged in cable in following form:

5 pairs of wires (single bunch) 10 pairs of wires (single bunch) 20 pairs of wires (single bunch) 50 pairs of wires (5 bunches of 10 pairs each)

Two types of JFCs are mainly used in India: Hindustan JFC Canedium JFC

4. Coaxial cable:Coaxial cable, commonly called coax, has two conductors that share the same axis. A solid or standard copper wire runs down then center of the cable, and this wire is surrounded by plastic foam insulation. Coaxial cable suffers less attenuation than either UTP or STP cable.

5. Sub marine cable

6. PCM cable (pulse code modulation)

7. PVC cable (poly vinyl chloride)

8. Microwave: used for the range of 45-75 km, it uses line of sight communication.

9. Satelite: range in the circles of 10000 km radius

10. Optical fiber cable (OFC):Fiber optic cable transmits light signals rather than electrical signals. Each fiber has an inner core of glass or plastic that conducts light. A layer of glass that reflects the light

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back into the core called cladding surrounds each fiber. The sheath can be either tight or loose.

Fiber optic cable is enormously more efficient than the other network cable media. It has much lower attenuation than copper wires, mainly because the light is not radiated in the way that electricity is radiated from copper cables. Current fiber optic technologies allow data rates from 100 mbps to 2gbps. Two disadvantages of fiber optic cable are that it is more expensive than other type of cable media and thus it is more difficult to install.

CABLING SYSTEM USED:

First of all subscriber is connected to DP box with the help of drop wire, the dp box contains the 10-20 pairs of screws, one pair is used for another subscriber. The dp box is connected to the CTB with the help of open wire, CTB is used for 50-100 subscribers, further CTB is connected to exchange’s MDF (main distribution frame), and then subscriber is provided connection to his desired destination by the exchange.

TYPES OF EXCHANGES:

Telephone exchanges are mainly of four types:

local exchange trunk exchange parent exchange main exchange

SWITCHING NETWORKS:

This is used for call transfers between two exchanges,The networks mainly used are as follows:

CDOT 128 (centre for development of telematics) E10B (electronic 10 digit basic version: an integrated telephone network) OCB

TYPES OF EXCHANGES AND SWITCHING NETWORKS

STUDY OF E10B EXCHANGE STUDY OF C-DOT SWITCHING NETWORK STUDY OF GSM

E10B EXCHANGE

ELECTRONIC 10 DIGIT BASIC VERSION

DIGITAL TIME DIVISION SWITCHING SYSTEM

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INTRODUCTION

The E10B system has been developed in terms of integrated telephone network, rather than individual telephone exchanges.It shares two fundamental principles with the original platon exchange:

-use of digital PCM techniques.-separation of the switching function (at exchange level) from the management functions (at network level)

The PCM system:The E10 B system has been developed for 30 PCM operations, but it can also handle 24-channnel PCM systems. Optical fiber and digital microwave links enable PCM techniques are currently being used for satellite communications with multiple access (TDMA) and demand assignment.

DECENTRALISATION OF FUNCITONS:This concept allows us to think exchange in terms of integrated network rather than in terms of individual exchanges.

Firstly, the telephone exchange is “expandable” in the physical sense of term. The subscriber connection unit is connected to the subscriber exchange via PCM links. There is thus need for it to be located on the site as the exchange itself. This implies that exchange can serve wide area using only one type of subscriber connection unit, linked to parent exchange by PCM systems. Common channel signaling (css) is used to carry data between control unit and remote subscriber connection units.

Secondly the management aids are shared by a no of exchanges. The operation and the maintenance centers responsible for each exchange, and also have access to all the data for the network that it controls.

SYSTEM STRUCTURE AND ORGANISATION:

An E10 B switching center can be divided into 3 main blocks:

Block 1: subscriber and circuit connections

Block 2: time division switching network,

Block 3 control unitBlock 4: operation and maintenance centre (OMC)

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SUBSCRIBER AND MULTIPLEX CONNECTIONS:

The unit is CSE 1000 electronic line concentrator. It provides for concentrating the traffic on 2,3 or 4 PCM links, corresponding to a maximum configuration of 120 circuits. The interface with the subscriber lines is via circuit boards comprising 16 ordinary subscriber equipment or 8 discriminated subscriber equipments. The control unit is microprocessor based and is duplicated due reasons of security.

After concentration, the analog signals are sampled and encoded to make up the outgoing PCM signals. A concentrator handling 1000 subscribers is housed in a standard 2-metre rack. It may be in the same building as the exchange (local concentrator: URAD), and serves remote subscribers connected to the exchange via 2,3 or 4 pcm links. This flexibility allows low populated regions to serve as well as urban regions.

The multiplex connection unit (URM) is connected to incoming PCM links from distant concentrators, time division exchanges, space division exchanges. In this case analog to digital conversion is necessary and where applicable, the matching of signaling, each URM has a total capacity of 32 PCM systems. Each URM is housed in one standard rack consists of 8 modules each with 4 PCM.

TIME DIVISION SWITCHING NETWORK:

This is three stage systems (time space time: TST). It provides 4-wire switching between the time slot allocated to the calling party and the time slot allocated to the called party.

When the ultimate capacity is reached, the E 10 B switching network can handle 384 PCM systems , 16 of which can be allocated to frequency sender/receiver units (ETA). The remaining 368 * 30 =11,040 time slots catering for 5,520 simultaneous calls.

The switching network is modular by steps of 64PCM systems. The maximum capacity switching network is housed in 4 standard racks.

CONTROL UNIT

The switching operations carried out in blocks 1 and 2 are monitored by the control units which constitute block3.

MR:

Calls are setup and released by the multiregisters, which operate in traffic sharing mode. A multiregister is microprocessor – based and compromise random access memories, which form the registers, each multiregister, for reasons of security six multiregisters are sufficient for a complete exchange, handling 52 call attempts every second, in busy hour conditions. Each multiregister occupies one standard rack.

TR: two translators contain the subscriber and trunk circuit files with all discriminatory data: correspondence b/w directory no and equipment no, classes of service, trunk groups, charging rate etc. each translator occupies one standard rack.

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TX: Two charging units generate the data required for invoicing subscribers. General or detailed billing is prepared, as required by subscriber. On the basis of rate applicable to a call, as supplied by the translator, the charging unit generates and totals metering pulses that take into account the charging mode. Each charging unit occupies one standard rack.

BT: A time base supplies all the timing signals required by the exchange. The master oscillator is triplicated for safety reasons.

MQ:Two markers handle the routing of data b/w the various units within the exchange.

ETA:The frequency sender receive units generate the tones directly in digital form. These groups also house the digital frequency receivers used for subscriber and trunk circuit MF signaling.

OC:This unit provides the interface to the operation and maintenance center.

OPERATION MAINTENANCE CENTER:

OMC handles system supervision. The center is provided with a non dedicated general – purpose minicomputer. Peripherals are provided for data storage (magnetic tape and is) and man/machine dialogue (high speed printers, VDU consoles, teleprinters).

Each OMC can handle up to 100,000 subscribers, distributed over no of exchanges. The connection to each exchange is provided by time slot in one of the network PCM links: the rate is therefore 64kbits/s.

The two main function of omc are as follows: network operations: network maintenance:

NETWORK OPERATION INVOLVES:

Exchange translator memory management:

-Modification of discriminatory data-modification of inter-exchange routing-creation of new trunk circuits and new circuit groups

1. Recording charging data sent out by the exchange and updating individual subscriber accounts.

2. Executing comprehensive tests outgoing subscriber lines and trunks circuits, and recording test results.

3. Monitoring the load and traffic handled by each exchange.

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NETWORK MAINTENANCE INVOLVES:

1 monitoring correct operation of the network by running continuous fault finding programs2 registering faults and operation anomaly signals3 reconfiguring any exchange when any unit thereof signals a serious fault and must be taken out of service4 Switching a faulty unit to test mode and analyzing resulting faulty signals to find out the faulty printed circuit.

PRINCIPAL FEATURES

CAPACITY 1 no of switchable PCM links: 3842 processing capacity: 190,000 BHCA3 traffic handling capacity: 4,000 erlangs4 transit exchange: 11,000 circuits5subscriber exchange: 45,000 lines and 5000 circuits

System1 time division switching 2 PCM TO CCITT and CEPT standards:-2mbit/s PCM link-30 telephone channels per PCM link-8 bits per telephone channel-adaptable to 24PCM links

3 stored program controls (SPC):-dedicated processors for switching functions-non dedicated processor for operation functions

SUBSCRIBER LINE1 dial or pushbutton VF telephones (CCITT standards)2 maximum resistances inclusive of telephone set: 2,500 ohms3. Ringing currents: 80v, 25 and 50 HZ (other frequencies to order)

ENVIRONMENTAL CONDITIONS1 exchange:- Ambient temperature of air drawn into racks: 18 to 20 degree Celsius.-relative humidity: 30 to 70 %

2 satellite exchange:-ambient temperature 5 to 35 deg Celsius.-relative humidity: 20 to 80%

MECHANICAL DATA

1 rack dimensions:-ht: 2m-width: 0.75m-Depth: 0.50m

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2 floor area:45,000 subscriber exchange=154 m211,000 circuit transit exchange=90m23 distributed floor loading:-less than 500 kg/m2

POWER SUPPLY 1. Exchange and satellite exchange: -48v2. OMC:220 V, 50 Hz

CENTER FOR DEVELOPMENT OF TELEMATICS

C-DOT DSS MAX is a universal digital switching system that is configured for different applications as local, transit or integrated local and transit switch. It has higher traffic load handling capacity up to 8, 00000 BHCA and with termination capacity of 40,000 lines as local exchanges or 15,000 trunks as trunk automatic exchange. The C-DOT DSS family is ideally placed to meet the different requirements of any integrated digital network.

Common cards and advanced components are used in the system hardware in order to reduce the no and type of cards. Standard cards, racks, frames and cabinets and distribution frames are used which facilitate flexibility in system growth. All these features together with buggerized.

Design make C-DOT DSS easy to maintain and highly reliable.

FLEXIBLE ARCHITECHTURE OF C-DOT:

C-DOT DSS is a modular and flexible digital system that provides economical means of servicing metropolitan, urban and rural environments the option of up gradation to add end features and services in future. Software is written in HLL ‘C’ and distributed over various processors and is structured as a hierarchy of virtual machines, the software are implemented communicating processes. The operating system provides message communication facilities such that the processes are transparent to their physical locations, for interprocess communication messages are exchanged over HDLC links that are implemented either as direct kinks oar switches network paths, the modules can be adds and existing modules can be added and existing modules can be modified without affecting other modules in the system.

TECHNOLOGY:

The system employs a TST switching configuration and is based on a 32- channel PCM structure. It uses a basic rate of64-kbps and 2-mbps primary multiplexing rate. Control distributed over the channel by using 32,16 and C-DOT DSS MAX is a universal digital switching system that is configured for different applications as local, transit or integrated local and transit switch. It has higher traffic load handling capacity up to 8,00000 BHCA and with termination capacity of 40,000 lines as local exchanges or 15,000 placed to meet the different requirements of any integrated digital network.

Common cards and advanced components are used in the system hardware in order to reduce the no and type of cards. Standard cards, racks, frames and cabinets and

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distribution frames are used which facilitate flexibility in system growth. All these features together with buggerized.

Design make CDOT DSS easy to maintain and highly reliable.

Flexible architecture of C-DOT:

C-DOT DSS is a modular and flexible digital system that provides economical means of servicing metropolitan, urban and rural environments the option of up gradation to add new features and services in future. Software is written in HLL ‘C’ and distributed over various processors and is implemented communicating processes. The operating system provides message communication facilities such that the processes are transparent to their physical locations, for interprocess communication messages are exchanged over HDLC links that are implemented either as direct links or can be modified without affecting other modules can be added and existing modules can be modified without affecting other modules in the system.

TECHNOLOGY:The system employs a TST switching configuration and is based on a 32 channel PCM structure. It uses a basic rate of 64-kbps and 2mbps primary multiplexing rate. Control distributed over the channel by using 32 ,16 and 8 microprocessors. All the critical circuiting has built-in in redundancy system hardware utilizes advanced concepts in microelectronic for a compact and optimum design. Basic memory unit has been implemented as a 16-MB dynamic RAM board. Single chip digital processors are used for implementing DTMF and MF receivers.

A high performance high density VLSI chip detects multiple tones and simultaneously performs signal filtering on four channels. This approach reduces cost, power dissipations and saves space on PCB’s. Analog to digital conversion of line circuits has been achieved by using a per channel coder-decoder (CODEC) chip.

BASIC GROWTH /BUILDING MODULES:

Using four basic modules can configure C-DOT DSS MAX exchanges

Base moduleCentral moduleAdministrative moduleInput-output module

BASE MODULE:

The base module is the basic growth unit of the system. It interfaces the external world to the switch. The interface may be the subscriber lines, analog and digital trunks, CCM andPBX lines. Each base module can interface 2024 terminations. The no of base module directly corresponds to the exchange size. It carries out majority call processing functions and in small exchange application; it also carries various operation and maintenance function with the help of input-output module.

In single base module (SBM) exchange configuration, the BM acts as independent switching system and provides connections to 1500 lines and output for bulk of data

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storage operation and maintenance functions. Clocks and synchronization is provided by a source with in the base module. It is useful for small urban and rural environment.

CENTRAL MODULE:

CM consists of a message switch and space switch to provide inter module communication and perform voice and data switching b/w base modules. It provides controlled message communication b/w any two BM and b/w BM and administrative module for operation maintenance functions. It also clock and synchronization on centralized basis.

ADMINISTRATIVE MODULE:

AM performs system level resources allocation and processing function on the centralized basis. It performs all the memory and time intensive call processing support functions and also administrative and maintenance functions. It communicates with base module. It supports the input output modules for providing ma machine interface. It also supports the alarm display panel for the audiovisual indication of fault in the system.

INPUT OUTPUT MODULE:IOM is a powerful computer system that interfaces various secondary storage devices like disk devices, cartridges tapes drives and floppy drive. It supports printers and up to 18 service ports for video display unit which are used for man machine communication interface. All the bulk data processing and storage is done in this module.

Thus a C-DOT DSS exchange depending upon its size and application consists of BM (maximum32), central module, administrative module, and IOM and alarm display panel.The BM can be remotely or co located depending on the requirement.

REMOTE SWITCH UNIT (RSU):

Remote switch unit is an integral part of C-DOT DSS architecture. In order to realize an RSU, the normal BM can be modified for routing with the host exchange via 2 mbps digital links. The no of 2 mbps digital links b/w main exchanges and RSU is primarily data mixed by the traffic.

A maximum of 16 PCM’s can be provided b/w RSU and main exchange. As for as call processing is concerned RSU is an autonomous exchange capable to local call completion. In case of failure of PCM links RSU goes into stand along mode of operation. In case it is not possible to process a call request due to unavailability of links to the host, the subscriber is connected to appropriate tone or announcement. During standalone mode of operation, the local and incoming terminating calls in RSU are switched and metering information of all the RU subscribers is stored in the RSU. It is send to the host whenever the PCM links are available again. Only even no of BM’s can be configured as RSU that is a maximum 16 RSU’s are possible in C-DOT DSS MAX*L and in MAX-L.

COMMON HARDWARE UNITS:

Various hardware units such as controller complexes and message switches have been standardized for multiple applications. This interchangeability is an important feature of

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the system hardware that helps in reducing inventories and increasing system availability. Some common hardware units are:

MODULE CONTROL UNIT

It is a 16 or 32 bit microprocessor complex with associated memory unit.

INTERFACE CONTROLLER:

This is an 8 bit microprocessor based unit with a time switching network that can be used to control certain terminal interface in the terminal unit or services circuit interface in the time switch unit.

MESSAGE SWITCH:

Message switch is implemented as a 32 bit message switch controller, which provides up to 38 HDLC/ADLC links for message communication b/w controller. In the BM the message switch can be implemented as 16 but message switch controller and a message switch card.

COMPUTER DIVISION:

This dept is responsible for the maintenance of computers used for networking, routing and data processing. The main job of this dept is classified as follows:

PC-maintenanceThis job is related with the maintenance of the following main components of a PC:-system box (or CPU)Input/output device or peripherals

COMPONENTS OF SYSTEM BOX (CPU):

motherboard hard disk floppy disk CD-ROM LAN card Multimedia sound card Microprocessor SMPS (switch mode power supply)

MOTHERBOARD:

The main components of motherboard are:

1. BUS (ISA,EISA,VISA,PCI,AGP SLAB,SCSI)2. RAM3. PROCESSOR

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4. CO PROCESSOR5. CHIPSET6. KEY BOARD CONTROLLER7. BIOS-ROM8. CMOS9. ADD ON CARDS

1 BUS

Buses are used to carry data and control signal from one component to another, earlier 3 separate buses were used to carry different types of signals as data, address and control. But now same bus can carry all the 3 types of signals. These buses are measured according to their capacity to carry data.As 8 bit & 16 bit resp from one component to another. Now some add on cards are inbuilt in the motherboard.

These different types of buses can be identified according to their color as

ISA BUS –BLACKPCI BUS- WHITEEISA,VISA-BROWN

2 HARD DISK DRIVE (HDD):

In the previous decade the hard disk that was used, has very low capacity of 512 mb. But the capacity increased and now capacity of 40 gb & 80 gb are available.

There are 2 types of HDD:i) IDE (integrated drive electronics)ii) SCSI (small computer system interface). IDE type hard disk uses a 40-pin cable & maximum 8 devices can be connected to this.SCSI type HDD comes in 2 categories, one having 50 pin cable and another having 68 pin cable used for server. Maximum 15 devices may be connected with this.

3. FLOPPY DISK DRIVE ( FDD):

It uses cable of 34 pins having 2 connectors. The middle connector is nearer to one end known as HEAD end; this decides the motherboard side connecter or FDD side connector. This cable has also twisted pair that indicates the FDD connector & this twisted pair decides the address for primary or secondary device.

4. ADD ON CARD:

Two types of cardsi) Display cardii) Controller card

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i) DISPLAY CARD: This card is for the control of displays on the monitor. It has 2 types of connector: 8 pin and 15 pin.

9-pin connector is called CGA having 2 lines of pins.15 pin connector is called VGA having 3 lines of pins.Now AGP (advance graphic package) are available as inbuilt card or external card.

ii) CONTROLLER CARD:

It comes as hard disk controller, printer interface cards etc. it has 3 types of connectors having 9, 34 and 40 pins.

9-pin connectors are used for mouse.34-pin connector is used for FDD.40-pin connector is used for HDD.

Now these cards are inbuilt in the motherboard. But still thse cards are used for emergency purpose, as I case of inbuilt failure.

5. BIOS:

It stands for basic input output system. It consists of permanent parameters and basically it is ROM.

6. CMOS

It stands for complementary metal oxide semiconductor. It consists of changeable parameters. It contains a battery for clock; password saving etc. this battery continues the clocks etc. though power is off. Earlier available battery was charged for 600 times but now latest cells are available which can be charged for 1200 times.

CABLES USED TO CONNECT 2 DEVICES:

These are 3 categories of cables used to connect two devices. These are:-

a) straight cableb) cross cablec) roll over cable

STRAIGHT CABLE:

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These cables are used to connect PC to switch or hub. The connections in these cables are as follows:

CROSS OVER CABLE:

These cables are used to connect 2 homogeneous devices like PC to PC. The connection in these cables is as follows:-

These cables are used to connect heterogeneous devices like PC to switch (console) or for configuring any network device. The connections of these are as follows:

(TX) 1(RX) 2(TX) 3(RX) 6

1 (TX)2 (RX)3 (TX)6 (RX)

(TX) 1(RX) 2(TX) 3(RX) 6

1 (TX)2 (RX)3 (TX)6 (RX)

12345678

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BSNL SERVICES

BSNL provides world class telephony service to the people of India. Each telephony connection has unique directory /telephone no and the facility to make and receive calls from any where in the world. The company provides 24 hrs customer care service. The company provides many customer services. The services provided by the company are as follows.

Fixed line telephony servicesTelemeetLeased linesInternet leased linesISDNVideo conferenceMobile servicesWLL mobile telephone connectionsMPLS based IP-VPN servicesFree phone servicesEPBAX

FIXED LINE TELEPHONE SERVICE:

These services provide end to end connectivity to subscribers with the help of various switching networks. Gone are the days when basic telephones were used only to make and receive calls. With the aid of state-of-the-art digital exchanges, BSNL offers you a host of phone plus services, converting your old basic telephones to a sophisticated tool, which can be used, for a variety of applications. New services added to this are:

Call waiting Abbreviated dialingHot line

TELEMEET:

BSNL tele is an audio conference service that enables the subscriber to conduct an audio meeting with participants located any where in the world.

Each participant can login to the audio bridge by dialing a particular no and by further entering the conference ID which is a unique no generated by the conference ID which is a unique no generated by the conference, thus ensuring correct access and absolutely security. BSNL offers two ways to conduct a meeting- dial in conference – here the

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proposed participants dial into the audio bridge conference no and join after entering the conference ID.

Dial out conference- in this scenario any no of te dial in participant can dial out to a particular no to include a new participant.

Benefits:

Reduces travel drasticallyReduces time Increases productivity

Leased lines:A leased line is a dedicated data connectivity providing subscriber withhighspeed connection b/w two or more locations. Leased liner can be within the city or intercity.A leased line normally bypasses the telephone exchange/switch and uses only the transmission/w i.e. backbone and haul to link two subscribers premises. Charging for leased line is done on a periodic basic and not per call basis. Leased lines provided by BSNL are available I the dominations of 64 kbps, nx64 and nx2 mbps. Point to point leased lines is used for transferring data from one point to another, while point to multipoint leased lines are used for transferring data among various locations.

CUSTOMER BENEFITS:

Secured managed network for ERP connectivityHigh network uptimeImmediate installationCost effectiveRound the clock service and problem resolution

An internet leased line (ILL) is a dedicated internet access services enabling access speeds of 64 kbps onwards. Ills enable all users on a LAN at the customer premises to access the internet from their desktop without having to dial up into the internet. This results in greater ownership, convenience and comfort, this service can also be utilized by the user to transfer high amount of data over internet and to establish vpn over internet. IIs come in various bandwidths ranging from 64 kbps onwards.

Benefits:

High speed internet access. Dedicated and uninterrupted connectivity. Higher reliability and uptime. Service level agreement for technical parameters.

INTEGRATED SERVICE DIGITAL NETWORK (ISDN) Isdn is a fully digital service that allows you to transfer voice, data and image simultaneously at high speeds over standard copper wires.

Isdn service is offered in two forms

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BRI (BASIC RATE INTERFACE)

BRI gives two 64kbps channels per line. By using these channels over a single copper wire, you can get speeds up to 128 kbps.

PRI (PRIMARY RATE INTERFACE)PRI consists of 30*64 a kbps channel giving a total bandwidth of 2 mbps. This is mainly used by companies handling large volume of data.

CUSTOMER BENEFITS:

All isdn lines are internet ready by default. Unlike basic telephone service, isdn functions on a digital platform, ensuring faster and noise free transmission. Call setup time b/w two isdn terminals is very low to the order of 2-3 seconds. High speed internet access and data transfer. High quality video conferencing at 128 kbps and 384 kbps. Capable of supporting analog device like G-3 fax and analog phones useful for backup support to leased lines.

VIDEO CONFERENCE:

A BSNL video conference service allows undertaking virtual meeting without being physically present at one location. This service enables two or more people at different locations to see and hear each other at the same. The participants of the videoconference can be located anywhere in the world. All they to have are the videoconference facility at their place and they can remotely participate in the meeting. This facility is very useful for schools, colleges and other institutes as with this technology even their remote branches can actively participate in the events like seminars and presentations by guest’s speakers.

ADVANTAGES: Time and cost saving with reduced need for travel. Real time experience with high tech n/w support lower setup cost.MOBILE SERVICES:

BSNL has launched CDMA based WLL mobile service in all over India under the brand name cell-one mobile. Cell-one mobile enables its customer to make and receive calls from anywhere in the world while on the move.

ADVANTAGES:

A world class network with superior voice quality, affordability – no airtime charges , free incoming calls from anywhere in the world, entire state accessible with 95 dialing facility.

Various value added services like – CLIP, call forwarding, call mgmt services, night speaks and Sunday speaks, dynamic STD/ISD locking.

Will is a communication system that connects customer to the public switched telephone network using the radio frequency signals as a substitute for the conventional wires for all or part of the connections b/w subscribers and exchange.

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MPLS BASED IP-VPN SERVICES:

MPLS (multi protocol label switching) VPN is technology that allows a service provider like BSNL to have complete control over parameters that are critical to offering its customers service guarantees with regard to bandwidth throughputs, latencies and availability. The technology enables secure virtual private network (vpn) to be built and allows scalability that will make it possible for BSNL to offer assured growth to its customers without having to make significant investments. BSNL would now be geared to provide bandwidth on demand, video conferencing, voice over ip (VOIP) and a host of other value added services that could revolutionize the way a corporate business works.

FREE PHONE SERVICES:

This service is an ideal business promotion tool for business communities who want their customers to call them free cost. Totally customer oriented organization can provide information about their products, allow customers to place orders or even register their complaints/suggestions and offer assistance to customers without the user getting charges.

EPABX

Bsnl permits telephone subscribers to use their own PABX/EPABX connected to the BSNL network under certain commercial/technical conditions. The type of subscribers premises will be permitted only on the specific approval of the concerned authority and charged as per dept tariff.

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GOALS AND RESPONSIBILITY OF BSNL

Access to telecommunication is of utmost importance for achievement of the country’s social and economic goals. Availability of affordable and effective communications for the citizens is at the core of the version and goal of the new telecom policy 1999.

Strive to provide a balance b/w the provision of universal service to all uncovered areas, including the rural areas, and the provision of high level services capable of meeting the needs of the country’s economy.

Encourage development of telecommunication facilities in remote, hilly and tribal areas of the country.

Transform in time bound manner, the telecommunication sector to a greater competitive environment in both urban and rural areas providing equal opportunities and level playing field for all players.

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