bsnl training report on ocb-283

5/9/2018 Bsnl Training Report on OCB-283

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AnIndustrial Training ReportOnDigital Switching System "OCB-283"

At

B H A R A T S I N C H A R N I G A M l T D ."KANPUR"

Submitted to: Submitted ByMr. R.S. TripathiS.D.E.(OCB-283)Telephone ExchangeSaket Nagar, Kanpur

Neeraj Sahu[JUIT, Solan]

Rohan Agnihotri[Amity University,Lucknow]

Ankit Singh Kushwaha[VIT,Vellore]


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COMPANY PROFILEBHARAT SANCHAR NIGAM LIMITED

Bharat Sanchar Nigam Limited (BSNL) is India's leading telecommunications provider andthe country's largest public-sector firm. It is fourth largest department of TelecommunicationCompany in Asia and seventh in world today. BSNL provides local-exchange access anddomestic long-distance services through a network of more than 45 million access linescovering most of India. It also offers wireless communications, data and Internet services, aswell as business voice and data services. The company is still controlled by the government,as is one of India's other large phone companies, Mahanagar Telephone Nigam Limited(MTNL). Plans to merge the two companies have been discussed but seem to be on hold.

HIGHLIGHTSqBharat Sanchar Nigam Limited has a vast reservoir of highly skilled and

experienced work force of about 3,57,000 personnel.qWe believe that our staff, which is one of the best trained manpower in the

telecom sector, is our biggest asset.qTo meet the technological challenges, employees are trained for technology

up-gradation, modernization, computerization etc in BSNL's training Centersspread across Country.qTo apex training centers ofBSNL i.e. Advance level Telecom Training Center

(ALTTC) at Ghaziabad and Bharat Ratna Bhimrao Telecom Training Centerat Jabalpur are comparable to any world class Telecom Training Center.Moreover, 43 zonal training centers and a National Academy of TelecomFinance and Management have been running for several years now.qDifferent curriculum run in these centers to impart technology based training,

training for Attitudinal change, basic educational and skill developmentprogram etc.


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PARTICULARS OF THE ORGANISATIONDate ofincorporation

Incorporated on 15.9.2000, vide Registration No. 55-107739, datedthe 15th September, 2000 and became entitled to commence businesswith effect from 19th September, 2000.The Company (BSNL) took over the .business of providing telecomservices and network management throughout the country except themetro cities of Delhi and Mumbai of the erstwhile service providingdepartments of the Govt. of India, i.e., the Departments of TelecomServices and Telecom Operations w.e.f. 1.10.2000 pursuant to anMoU signed between the BSNL and the Govt. ofIndia.

Type of Company Government Company under Section 617 of the Companies Act,1956.

Administrative Govt. of India, Ministry of Communication and InformationMinistry Technology, Department of Telecommunications.Details of The entire share capital of the Company is held by the Govt. ofIndiaDisinvestmen ts

Shareholdingpattern Government of India is holding 100% of the share capital of theCompany

Listing with Stock Not applicable, as the BSNL is an unlisted companyExchanges

Share Capital Authorized Capital - Rs.17,500 crores, divided into1,000,00,00,000[One Thousand Crores] Equity Shares of Rs.101-each; and 750,00,00,000 [Seven Hundred and Fifty Crores]Preference Shares ofRs.101- eachPaid Up Share Capital - Rs.5,0001- crores of Equity Shares andRs.7,5001- crores of Preference Share Capital


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VISIONTo become the largest telecom Service Provider in South east Asia.MISSION- To provide world class State-of-art technology telecom services on demand ataffordable price.- To Provide world class telecom infrastructure to develop country's economy.

PROFILE OF THE COMPANY'S BUSINESSA. GLIMPSES OF MAIN SERVICES OFFERED

1. BASIC AND LIMITED MOBILE TELEPHONE SERVICESBSNL is the leading service provider in the country in the Basic Telephone Services.

As of now more than 35 million Direct Exchange Lines & more than 2.2.Million telephonesin the Limited Mobile telephone Services are existing. BSNL has provides a number ofattractive tariff packages & Plans which shall further strengthen its subscriber base.

2. CELLULAR MOBILE TELEPHONE SERVICESBSNL's GSM Technology based Cellular Mobile Network has reached a long way, coveringmore than 6400 towns, with a subscriber base of over 1.54 crore as on 31st Jan. 2006 out ofwhich 1.16 Crore cellular telephones are in the prepaid segment.

3. INTERNET SERVICESBSNL offers Dialup Internet services to the customers by Post-paid service with the brandname 'Netone', and pre-paid service with the brand name 'Sancharnet'. The post-paid serviceis a CLI based access service, currently operational in 100 cities. Sancharnet is available onlocal call basis throughout India to ISDN and PSTN subscribers. The Internet Dhaba schemeof the Company aims to further promote Internet usage in rural and semi urban areas.To keep pace with the latest and varied value added services to its customers, BSNL usesIP/MPLS based core to offer world class IP VPN services. MPLS based VPNs is a veryuseful service for Corporates, as it reduces the cost involved as well as the complexity insetting up VPNs for customers networking. As on 31.03.2005, your Company's total Internetcustomer base was 17,98,089 and total Internet Dhabas were 4143. A total of708594 dial up


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Internet connections have been given during 2004-2005, against a target of 7 lakhs. BSNLplans to give 1215980 more dial up connections during the year 2005-06. As on 31.1.2006,there were 2367404 internet subscribers working in BSNL net work.

4. INTELLIGENT NETWORKIntelligent Network Services is a service that incorporates several value added facilities,thoroughly designed to save time and money, and enhance productivity. At present, yourcompany offers Free Phone (FPH), Premium Rate Service (PRM), India Telephone Card(lTC), Account Card Calling (ACC) , Virtual Private Network (VPN) , Universal AccessNumber (UAN) and Tele voting IN services. With the commissioning of five numbers ofnew technology IN Platforms (Four General purpose and One Mass Calling) at Kolkata,Bangalore, Ahmedabad and Hyderabad, the India Telephone Card facility and new valueadded services are being provided throughout the country. Activation of these new INplatforms had increased the sale of ITC Cards taking the figure to Rs.265 crores in 2004-05alone.

5. BROADBAND SERVICES

BSNL has launched its Broadband Services under the brand name 'DataOne' on 14/1/2005.This offers services like High Speed Internet Access with speed ranging from 256 Kbps to 8Mbps. Other services like streaming video, Video on Demand, Bandwidth on demand etc.,have also been planned. As on 31.12.2005 , there were more than 356000 broad bandconnection provided by the BSNL. There are plans to give 2 million and 3 millionconnections in 2006 and 2007 respectively.B. DEVELOPMENT OF RURAL TELECOM NETWORK

1. Rural DELsAs on 31.03.2005, in BSNL's network, a total of 1.356 crore rural telephone connectionswere working. As on 31.1.2006, there are 1.425 crore rural telephones working in BSNLnetwork.

2(a). Village Public Telephones (VPTs) & RCPs:-BSNL, in its unstinted efforts to make the slogan 'Connecting India', a reality, had providedVPTs in 5,18,992 villages up to 31.03.2005. The Company entered into an agreement with


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usa Fund for expansion of rural telecom network by November 2007, by providing VPTs in66,822 undisputed, undisturbed, accessible and inhabited villages having population morethan 100 as per Census, 1991 in the country. BSNL provided VPTs in 5,28,886 villages upto 31.01.2006. There are plans to replace all MARR VPTs in the country. As of now total123194 MARR VPTs already replaced in the country by BSNL. BSNL also committed toprovide the Rural Community Phones as per the usa Fund agreement. As of now around13713 RCPs already provided by BSNL.2(b). Public Telephones:-There are more than 2 million PCOs working in the BSNL Network out of which around 1million PCOs are having STD/ISD.

c. NETWORK MANAGEMENTBSNL is committed to provide a robust state of the art infrastructure that will provide stableand superior services to its customers. Accordingly, the MLLN network covering more than200 cities was made operational in May 2004. Since then, about 22000 circuits have beenprovided on this network. This has provided high level of stability to the leased circuits andcapability to offer N X 64 Kbps circuits. Keeping in view the growing demand of leasedcircuits, the network is being expanded to cover about 50 more locations and additionalcapacity at many existing locations is also being provided.To improve the operational efficiency of CCS 7 signaling, stand-alone signaling transfer point(SSTP) equipment is being procured. This will also enable the Company to measure signalingtraffic of other operators, who are using its signaling network for exchanging messages,specially with regard to cellular services. BSNL has more than 4.7 Lakhs Route Kilometers ofoptical fibre network in the country & has installed capacity more than 6.4 million lines for theTAX meant for the STD/ISD network.

D. Setting up KU Band VSAT networkAs regards the KU Band VSAT network equipment, the hub of this network is being set up atBangalore, The equipment has been installed and expected to be commissioned shortly. Thiswill help your Company, to become a service provider with all types of media equipment i.e.OFC, Microwave and satellite for provision of bandwidth, this will also enable the Company tooffer composite solutions to its customers.


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E. Policy on transmission network maintenanceTelecom Circles have large transmission networks. To improve the maintenance oftransmission network, guidelines for route parties and vehicles have been formalised. TelecomTerritorial Circles are also being connected with computerised network for booking oftransmission system faults, with a view to improve follow up and faster restoration of faults.

F. Annual Maintenance contracts for switching system &WLLComprehensive AMC, which includes hardware and software maintenance and upgrade, hasbeen arranged with the respective equipment suppliers. Initial feedback suggests that, as aresult of preventive and corrective maintenance support, the performance of switches isimproving. Difficulties in entering into AMC with rural WLL equipments suppliers have beenresolved and procedures streamlined so that adequate maintenance support becomes available.As a result, the performance of WLL network is improving. AMC arrangements have also beenmade with suppliers of FWTs and hand held terminals.G. COMPUTERISATIONImplementation of Inter Operator Billing and Accounting system (IOBAS) has beencompleted. Your Company plans to provide CDR based Customer Care and ConvergentBilling system. This will help Company in providing effective and efficient billing &customer care solutions for its fixed line subscribers. It envisages building of country wideintranet to reduce the cost of operation, increase realization, stop leakage of revenue andminimize frauds, besides providing round the clock best customer care services to theCompany's subscribers.

Call center facility has been introduced for 71 SSAs, which is a single point approach foraddressing all customer needs cum grievances. Web based Public grievance ManagementSystem has been implemented for speedy disposal and monitoring of public grievances. Webbased Inventory Management package has also been introduced, through which, materialmanagement functions are being computerized gradually in different circles. Online MobileBill viewing facility has been made available to all Cell One Mobile Customers (all States)through Company's Portal (http://bsnl.in). Duplicate Telephone bill viewing facility forlandline telephone has also been made available at many places through Websites ofrespective telecom circles.


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H. OBLIGATIONS1. Towards customers and dealersTo provide prompt, courteous and efficient service and quality of products/services at fairand reasonable services.

2. Towards employees Develop their capability and advancement through appropriate training and careerplanning Expeditious redressed of grievances Fair dealings with recognized representatives of employees in pursuance of healthy

trade union practices and sound personnel policies

3. Towards the Society -Corporate Social ResponsibilitiesBSNL is committed to provide quality Telecom Services at affordable price to the

citizens of the remotest part of the Country. BSNL is making all effort to ensure that the mainobjectives of the new Telecom Policy 1999 (salient points indicated below) are achieved:

Access to telecommunications is of utmost importance for achievement of thecountry's social and economic goals. Availability of affordable and effective communicationsfor the citizens is at the core of the vision and goal of the new Telecom policy 1999.

Strive to provide a balance between the provision of universal service to alluncovered areas, including the rural areas, and the provision of high-level services capable ofmeeting the needs of the country's economy encourage development of telecommunicationfacilities in remote, hilly and tribal areas of the country;Transform in a time bound manner, the telecommunications sector to a greater competitiveenvironment in both urban and rural areas providing equal opportunities and level playingfield for all players.


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I. Assistance during natural calamitiesBSNL always remains awake of its responsibility as a corporate citizen. When the destructiveTsunami waves struck the Indian shores, BSNL Company swung into action immediately forproviding relief to those affected in the coastal areas. Communication networks at the Coastalareas of Tamil Nadu, Kerala and the Andaman and Nicobar Islands - worst hit in theTsunami - were promptly restored within the shortest possible time. BSNL along with theemployees contributed an amount of Rs. 2,207 lakhs to the Prime Minister's Relief Fund.Telephone Services were restored in record time in the flood-hit areas of Gujarat andMaharashtra.

J. Manufacturing Units:Telecom factories to manufacture telephone switching boards and accessoriesat Bhilai, Mumbai, Calcutta and Jabalpur. 1.T.1.Bangalore for the manufacturing for the carriers, VFT, Coaxial andmicrowave equipment. 1.T.1. Gonda for the manufacturing of E-l OBelectronic exchangeequipment. Hindustan Cables LTD. Hyderabad & Rupnarainpur for manufacturingunderground cables. Hindustan teleprinters LTD Chennai for manufacturing teleprinters


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HISTORY OF TELEPHONE EXCHANGEThe word telephone, from the Greek roots tele, "far," and phone, "sound," was applied asearly as the late 17th century to the string telephone familiar to children and was later usedto refer to the megaphone and the speaking tube; but in modern usage it refers solely toelectrical devices derived from the inventions of Alexander Graham Bell and others. TheU.S. patent granted to Bell in March 1876 for the development of a device to transmit speechsounds over electric wires is often said to be the most valuable ever issued. The generalconcepts involved in the invention of the telephone -- of speech sounds as a complex ofvibrations in air that is transferrable to solid bodies and of the convertibility of thosevibrations to electrical impulses in conducting metals - had by then been understood fordecades. Bell was but one of a number of workers racing to pull them together into apractical instrument for the transmission of speech. Within 20 years of the Bell patent, thetelephone instrument, as modified by Thomas Watson, Emil Berliner, Thomas Edison, andothers, acquired a form that has not changed fundamentally in a century. Since the inventionof the transistor in 1947, metal wiring and other heavy hardware have been replaced bylightweight and compact micro circuitry. Advances in electronics have improved theperformance of the basic design, and they also have allowed the introduction of a number of"smart" features such as automatic redialing, call-number identification, and analog- to-digital conversion for transmission over digital circuits. Such advances supplement, but donot replace, the basic telephone design. As it has since the early years of telephonecommunication, the telephone instrument comprises the following functional components: apower source, a switch hook, a dialer, a ringer, a transmitter, a receiver, and an anti-sidetonecircuit.

Like the Ocean that is made of tiny drops, the P&T had a slow and uneasy start.The sprawling Posts and Telegraphs Department, for instance, occupied a small corner of thepublic works department, in 1851. Dr. William O'Shaughnessy who pioneered telegraphand telephone in India belonged to the Public Works Department all through theexperimental stage. A regular, separate department was opened around 1854 when telegraphfacilities were thrown open to the public.The Telegraph Department during 1854-57 comprised a Superintendent of Telegraphs, withthree Deputy Superintendents at Bombay, Madras and Pegu in Burma. There were Inspectorsat Indore, Agra, Kanpur and Banaras and an operating and maintenance staff. Dr.O'Shaughnessy was the first Superintendent of Electric Telegraphs in India and later becamethe first Director General. The Indo-European Telegraph Department, which later came to beknown as the Overseas Communications, was administered by a Director-in-Chief whoseheadquarters was in London. On the 15th February, 1888, it was merged with the Director-General of the Indian Telegraph Department. Itwas decided that the administration reports ofthe two departments, Indian Telegraph and the Indo-European Department, should be


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separated so as to show how the finances of the country were affected by each unit. Theoperations of the two separate services, Post Office and Telegraph Department developedside by side. On the eve of World War I, in 1914, the next big administrative change came.The Postal Department and the Telegraph Department were amalgamated under a singleDirector-General. The process had started in 1912, but it was completed in 1914. During1923-24, 152 questions relating to the Department were asked and answered in the IndianLegislative Assembly. Posts and Telegraphs has always evoked a great deal of interest fromlaw maker.A major reorganisation of the department took place in April, 1925. The accounts of theIndian Posts and Telegraphs were reconstituted to examine the true fiscal profile of thedepartment. The attempt was to find out the extent to which the department was imposing aburden on the taxpayers or bringing in revenue to the Exchequer, how far each of the fourconstituent branches of the department, the postal, telegraph, telephone and wireless werecontributing towards this result. It was further examined whether the rates charged from thepublic for the various services were inadequate or excessive .The Posts and Telegraphs, likeall public and private undertakings, was a victim of the universal financial and economicdepression which crashed on the world in 1930. During 1931, numerous economy measureshad to be introduced according to the advice of the Posts and Telegraphs Sub-Committee tothe Retrenchment Committee presided over by Sir Cowasjee Jehangir Jr. Naturally, theadoption of the various measures of retrenchment could not but have an adverse effect on theemoluments and interests of the personnel of the Department.From the beginning, P&T set up was run on welfare lines. Profit was not the motto. Theannual report of the department for 1931 said "It is the accepted policy of the Governmentthat the department should be so administered that there should be neither any substantialprofit nor any substantial loss on its working under normal conditions. As has already beenindicated, the achievement of this ideal has not proved possible owing mainly to theexceptional economic and trade conditions of recent years. One of the main contributorycauses was the revision and improvement of pay of the great bulk of the employees of thedepartment in recent years. This was undertaken with the approval of and indeed underpressure by the Legislative Assembly. While the department is commonly spoken of as a'commercial' one and though as far as possible it is guided by the commercial considerationsin the regulation of its business, it must be realised that in many directions it is debarred fromobserving strict business principles. Many of the purposes which it is required to serve areenumerative and notably, in matters relating to the employment and control of staff, thedepartment is bound by a large volume of statutory and other rules, doubtless necessary forthe regulation of a public service, but which in the aggregate involve many restrictions of akind unknown to private commercial concerns.

After the implementation of the Federal Financial Integration Scheme of 1stApril, 1950, the administration of the entire network of telegraph and telephone systems ofthe nation, including those that previously existing in the former princely states became a


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major adventure. In 1950 the number of Telephone Exchanges absorbed from princely stateswas 196. These systems which were working with different degrees of efficiency could fitinto the general telecommunication network. The installed capacity of these 196 exchangeswas 13,362 lines with 11,296 working connections. Soon after the absorption an attempt wasmade to improve their technical efficiency by replacing obsolete and unserviceableequipment and lending well-qualified and experienced staff. Simultaneously, isolatedexchanges were integrated with the general pool. The more complicated task was acquisitionof the staff. Their final absorption into the different cadres of service in Posts and Telegraphswas a major step.Till 31st December, 1984, the postal, telegraph and telephone services were managed by thePosts and Telegraphs Department. In January 1985, two separate Departments for the Postsand the Telecommunications were created.

The Department in 1986 reorganised the Telecommunication Circles with theSecondary Switching Areas as basic units. This was implemented in a phased manner.Bombay and Delhi Telephones were separated to create the new entity called MahanagarTelephone Nigam Ltd.(MTNL). On 1st October 2000, Department created BSNL, a newentity to operate services in different parts of the country as a public sector unit.

INTRODUCTION TO ELECTRONIC EXCHANGEPreviously electro mechanically exchanges for use in India namely Strowger type

exchange, cross bar exchange were there. These manual telephone exchanges suffered fromsome disadvantages.

To overcome the limitations of manual switching, automatic exchanges havingelectromechanical components were developed. Strowger exchange the first automaticexchange having direct control features was invented. Though it improved over theperformance of manual exchange, it still had a number of disadvantages, viz, a large numberof mechanical parts, limited availability, inflexibility, bulky size, etc. As a result of furtherresearch and development, cross bar exchanges having indirect control features appearedlater on. Cross bar exchanges improved upon many shortcomings of the strowger exchanges.However much more improvement was expected and revolutionary change in the field ofelectronics provided it. A large no. of moving parts in registers, markers, translators, etc. wasreplaced en-blocked by single computer. This made the exchange smaller in size, volume andweight; faster and reliable; highly flexible; noise free; easily manageable with no preventivemaintenance etc.

In 1980's PITHROTHA LTD. Introduced" C-DOT " exchange in India. Theseexchanges replaced by electro mechanical exchange. These exchange which has wide range


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of capacity replaced electro mechanical exchange, C-DOT-128, C-DOT-256, C-DOT-512,C-DOT-1024(SBM) exchange, C-DOT-2048(MBM) exchange and so on.Besides C-DOT exchange IL T exchange, E-10B exchange also proved of mild stone IIITelecommunication Sector to replace electromechanical exchanges, which were mostsophisticated and modern latest techniques electronics exchanges.There after it was OCB-283 exchange which proved very important exchange in this series toreplace electro mechanical exchanges .Now it is "WLL" & "GSM" mobiles which is alsoproved a mild stone in Telecommunication sector. It was 31st march 2002 when BSNLstarted these GSM mobile and today it has provided almost 35 laces mobiles in all overcountry. WLL system which is also a mobile with limited mobility in city & can have Telecommunication facility in that area almost. While GSM can cover all cities of the country ..The first electronic exchange employing space division switching (analog switching) wascommissioned. This exchange use one physical path for one call and hence full availabilitycould still not be achieved. Further research resulted in development of time divisionswitching (digital switching) which enables sharing a single path by several calls, thusproviding full availability.

In manual telephony, the type of exchange used is Central Battery (C.B.). In certain caselocal battery exchange (L.B.) is also used. The local battery exchange is also called magnetexchange because the set has a magneto generator which the subscriber is required to rotate,to generate the A.C. necessary to operate the indicator at the exchange.

In the central battery exchange, the battery is located at the central placewhich is the exchange. This arrangement has many advantages over L.B. exchange & can beused for even for large & medium capacity exchange.

In automatic telephony connections between two subscriber are establishedwith the help of human operator. Obviously the junction of human operator is carried out bythe machine known as switching or selector stages. After the development of automatictelephone exchange technology as a subscriber directly & it has many advantages overmanual telephone exchange. Nowaday electronic Automatic exchange is widely used due totheir advantages.

Year187619151920195619621965197419771980s1990s

IncidentsInvention of Telephonefirst transcontinental telephone(NY -SF)first automatic switchesTAT-1 transatlantic cables(35 lines)Digital transmission(T1)lESS analog switchesInternet packet voice4ESS digital switchesSignaling System (out-of-band)Advanced Intelligent Network (AIN)


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ADVANTAGES OF ELECTRONIC EXCHANGES OVERELECROMECHANICAL EXCHANGES In electromechanical exchanges category analysis, routing, translation, etc., is done byrelays while in electronic exchanges translation, speech path, subscriber facilities, etc., aremanaged by map and other data. In electromechanical exchanges any change in facilities require addition of hardwarechanges whereas in electronic exchanges changes can be carried out by simple commands. Electromechanical exchanges have limited flexibility while electronic exchanges arehighly flexible. Testing is done manually externally and time consuming process in electromechanicalexchanges whereas in electronic exchanges testing is carried out automatically analysis isprinted out. In electromechanical exchanges, there is partially full-availability hence blockingproblem is there. Electronic exchanges are fully available hence no blocking. Limited facilities are available to subscriber in electromechanical exchanges thanelectronic exchanges. Electromechanical exchanges are slow in speed as compared to electronic exchanges. Switch room occupies large volume in electromechanical exchanges. There is lot of switching noise in electromechanical exchanges as compared to electronicexchanges. Longer installation time is required in electromechanical exchanges.


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TELEPHONE LINESTelephone lines are very important in telephone exchange. By the cable the subscriber is

connected with each other. In the whole process, we use two types of cable:1. Switching Board Cable(S.B . cable)2. Under Ground cable(U.G. cable)

SWITCH BOARD CABLE: S.B. cable is used for the indoor process. By this cable weconnect exchange to the M.D.F. room. This cable has pairs. One S.B. cable has eight gaps &each gap has eight pair. One gap is connected with a L.C.C.(Line Circuit Card) & Onemodule. The Cable is Connected to left switch of module.

COLOUR CODING OF S.B. CABLE: There are two colours wire in one pair. Onecolour is called prime colour & other one is called made colour.PRIME COLOUR:1. Blue 2. Orange3. Green 4. Brown 5. Slate

MADE COLOUR:1. White 2. Yellow3. Black 4. RedColour Combination of S.B. cable:1. Blue-White 2.Brown- White 3. Orange-White4. Green-White 5 . Slate-White 6. Blue-Red7. Orange-Red 8. Green-RedThere are Eight different colors of wraps in S.B. cable which are given below:1. White 2. Yellow 3. Brown 4. Blue5. Grey 6. Black 7. Pink 8. Green


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UNDER GROUND CABLE: u.G. cables are used for outdoor process. By the cablewe connect M.D.F. to subscribers from there left-right to a module. This cable has hundredpairs to thousands of pairs. There is twenty pair in one band.COLOUR CODING IN U.G. CABLE: In one pair there are two colour wires. In thisfirst is called Primary Color & other is Made Color like S.B. cable. Chart of color coding isgiven below:

Made WHITE RED YELLOW BLACKcolourPrimecolourBlue 1 6 11 16Orange 2 7 12 17Green 3 8 13 18Brown 4 9 14 19Slate 5 10 15 20

*The pair of colour is made according to this chart respectively


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OCB-283Telecommunication networks are constantly changing. The rapid growth of the digitalnetwork, mobile network and intelligent network and the proliferation of new services beingconstantly offered to subscriber means that equipment must be continuously adapted to newrequirements. All new technology switching systems are based on Stored Program Controlconcept. The call processing programs are distributed over different control organs of thesystem and are stored in ROM / RAM of different control units. Processor in the control unitsby using the program and data stored in unit ROM / RAM process and handle calls. Handlingor processing call means to ultimately establish a connection in a switch between i/c and o/gends. Depending on the name and architecture of control units and switch may change butcriterion for switching remains more or less the same.

OVERVIEW OF OCB-283The Aicatell000EI0 exchange also known by its other name OCB283, is designed to

cater for evolving networks and the need to rationalize equipment operation. Its modulararchitecture means that new services can be added and processing capacity can be increasedwithout interrupting operation of the exchange. OCB 283 is a digital switching system whichsupports a variety of communication needs like basic telephony, ISDN, interface to mobilecommunication, data communication etc. This system has been developed by ALCATEL ofFrance and therefore has many similarities to its predecessor E-I0. The first OCB283exchange of Rll version came to India in 1993. At present R23 and R24 are also beingsupplied. The basic architecture remaining same, more facilities to subscriber andadministration are supported by later versions.

0-------- ORGANC-------- COMMAND OR CONTROLB-------- BOARD2--------- lIND GENERATION83------- MICRO PROCESSOR UNIT

SALIENT FEATURES OF THE SYSTEM1. It is a digital switching system with single 'T' stage Switch .Amaximum of2048.2. It supports both analog and digital subscribers.3. The system supports all the existing signaling systems, likes decadic, MF (R2), CAS and

also CCITT#7 signaling system.4. It provides telephony, ISDN, Data communication, cellular radio and other value added

services.


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5. The system has 'automatic recovery' feature. When a serious fault occurs in a controlunit, it gives a message to SMM (0& 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. Diagnosticprograms are run on the faulty unit and diagnostic is printed on the terminal.

6. OCB -283 has double remoting facility. Subscribers access unit CSND can be placed at aremote place and connected to the main exchange through PCM links .Further, lineconcentrators can also be placed at a remote location and connected to the CSNL orCSND through PCMs .This special feature can meet entire range of necessities viz urban,semi urban and rural.

7. Various units of OCB 283 system are connected over token rings (IEEE 802.5standard).This enables fast exchange of information and avoids complicated links andwiring between various units.

8. The charge accounts of subscribers are automatically saved in the disc once in a day .Thisavoids loss of revenue in case of total power supply/battery failure.9. The traffic handling capacity of the system is huge .It can handle 8,00,000 BHCA and10,000 erlangs of traffic. Depending on the traffic, a maximum of 2, 00,000 subscriberson 60,000 circuits 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 a station.

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

12. The OCB 283 systems are made up of only 35 types of cards. This excludes the cardsrequired for CSN .Because of this the number of spare cards, to be kept for maintenanceare drastically reduced.

13. The system has modular structure .The expansion can be very easily carried out byadding necessary hardware and software.

14. The SMMs (0 & M Units) are duplicated with one active and other hot standby .In caseof faults, switch over takes place automatically. Moreover, as discs are connected to bothSMMs, there is no necessity of changing cables from one system to another.

15. The hard disc is very small in size, compact and maintenance free.16. It has a very huge memory capacity of 1.2 Giga bytes .The detail billing data are

regularly saved in the disc itself, from where they can be transferred to magnetic tape forprocessing.17. The space requirement is very small. No separate room is required for OMC.18. There is no fixed or rigid rack and suite configuration in the system .It provides great

flexibility and adjustment in the available space.19. The environment requirements of the system are flexible. False floor and ceiling are not

essential .Air conditioning requirements are also not stringent .The system can work atemperature 5 to 45 C, though the optimum temperature is 22 C.


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Subscriber Facilities Provided by OCB283Itprovides a large number of subscriber facilities. Some facilities are available to only digitalsubscriber and as such they can not be availed by analogue subscribers. To avail thesefacilities subscriber number are given special categories by man machine commands.

A line can be made only outgoing and incoming. Immediate hotline facility - The subscriber is connected to another predetermined

subscriber on lifting the handset, without dialing any number.

Delay hotline facility - When subscriber lifts the handset, dial tone is provided, hecan dial any number. If he does not dial a number, within a predetermined time,he is connected to predetermined number.

Abbreviated dialing - The subscriber can record a short code and itscorresponding full number in the memory. Later to dial this number he has to dialonly short code of that number.

Call waiting indication - When a subscriber is engaged in conversation and ifgetting an incoming call, an indication is given in the form of a tone. Hearing this,the subscriber has option, either to hold the subscriber in conversation and attendthe waiting call or to disconnect this subscriber and attend to the waiting call. Inthe former case he can revert back to the earlier subscriber.

Call forwarding - When provided, incoming calls to the subscriber getstransferred to the number mentioned by the subscriber while activating thefacility. This facility is especially very useful for those person who are always onmove.

Conference between 4 subscribers - The subscriber A & B while in conversation,can include two more subscriber by pressing '* button' and dialing their numbers. Automatic call back on busy - If this facility is activated and if the called

subscriber is found busy, the calling subscriber simply replaces the receiver. Thesystem keeps watch on the called subscriber and when it becomes free, a ring isgiven to both the subscribers. On lifting they can talk to each other.

Priority lines - Calls from these lines are processed and put through even whenthe number of free channels are within a threshold or when the system isoperating in catastrophic mode.


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Malicious call identification - When this category is given to a subscriber, thenumber of calling subscriber, the number of calling subscriber to this number isprinted on the terminal or displayed on the caller identification instrument.

12 or 16KHz meter pulses - The system can send 12 or 16KHz meter pulses onthe subscriber line for the operating of the home meter.

Battery reversal - The system extends battery reversal when called subscriberanswers. This is useful in case of CCBs( Coin collection box ).

Detailed billing - The system provides detail bills given details of date, time,metered units etc.

Absent subscriber service - When activated, the incoming calls are diverted toabsent subscriber service for suitable instruction or information.

It provides 64 Kb/s digital connectivity between two subscribers for datacommunication.

This system provides Facsimile (FAX) services and videotext services also. This system also provides the facility for restriction of the display of calling

subscriber number on called subscriber's telephone terminal or caller id set. Toavail this facility the subscriber has to be given a category like some VVIPs orsome bureaucrats.

User to user signaling - The system permits of mini messages between callingand called subscribers during call setup and ringing phase.

Terminal portability during the call - A subscriber (calling subscriber as well ascalled subscriber) can unplug telephone instrument, carry it to some other place orroom and resume the call within 3 minutes

Listing of unanswered calls - The number of calling subscribers, who calls duringthe absence of called subscriber, are recorded in called subscriber's terminal. Thecalled subscriber than check up these numbers and call them back, ifhe so wishes.

This system provides two type of ISDN connections to the digital subscriber, oneis of 2 B + D Line (2 voice channels of 64kbps & I data channel of 16kbps) typeand other is of 30 B + D Line (30 voice channels of 64kbps & 1 data channel of16kbps) type.


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TIME SWITCH CONCEPTThe time switch comprises of a Speech Buffer Memory, A Control Memory, An IncomingHighway Of Digital Speech In Parallel Bits and An Outgoing Highway. This is an InputAssociated Controlled Time Switch. In this switch the Buffer Memory and Control Memoryare controlled write type i.e. the writing in it is controlled. The control function writes in thecontrol memory at the location corresponding to the Incoming Time Slot Number, thelocation where it should be written in the Buffer Memory. Both these memories aresequential read type. Reading of control memory gives the address in the Buffer Memory forwriting Incoming TS Byte. Thus reading of Buffer Memory sequentially the TS will be readfrom the location given by the Control Memory. Thus a one way Time switching has takenplace. Similarly a both way switching requires two sets of such switches.DUPLICATED SWITCHINGThe switching is done in OCB-283 in two fully duplicated branches simultaneously. For thispurpose from each connection units the LR links originate in two parallel branches towardstwo parallel sets of switching matrices called SMX A and SMX B. The branches of suchnetwork are called A and B branches. Also the receive side LR links come from both theSMX's A & Band 18 are terminated on the respective connection units. The duplicatedbranches of switching have been designed to provide high reliability switching path for suchdiverse purposes as data switching, video conference, ISDN applications etc.

With the duplicated paths of switching if there is error in one path the otherpath which is good can be used continuous 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 arrangements. Also they have non duplicated hardware such assubscriber cards and PCM termination cards. The duplicated LR's originate from a functionin connection units called SAB-Selection And Amplification Of Branches. It's role is togenerate two sets of LR' s in trans-direction with calculation of parity etc. In receive directionit gets data from both the branches which it checks for parity and compares to detect anyerror in the two branches. In case of error the samples from only the good branch are takenafter automatic testing of the quality of transmission of both the branches by the commoncontrol and the faulty branch is withdrawn from the service. The connection units lr links areformed into group of 8 LR's at the factory into cables with both ends terminated with plugsfor the convenience of installation. Such groups ofLR's are called GLR.


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Common Channel Signaling No.7 (CCS#7)

IntroductionThe latest signaling now being implemented worldwide is Common Channel Signaling oralso called CCS#7 signaling. This type of signaling is essential for the setting up of the ISDN(Intelligent Services Digital Networks) services.

In this type of signaling the Signaling information is sent from one exchange to otherexchange (called signaling points SP) in the form of Messages coded in Binary form, whichis understandable by the intelligent devices available at both the ends means in both theexchanges. The CCITT (Consultative committee on international telecom treaty)organization has recommended a standard protocol called CCITT#7 signaling. The signalingmessage travels over a single Time Slot of the PCM connecting the two exchange (SignalingPoint SP). This time slot is called Common Channel for signaling, hence the name commonchannel signaling. The message over this common channel carryall relevant data for any ofthe other Time Slots or Circuits which carry Voice or Subscriber data. The channels forsubscriber are called Voice Channels.

VOICE CHANNELS

EXCHANGEA EXCHANGEB

For Signaling

bsnl training report on ocb-283

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