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ROYAL INST. OF MGT & TECH.
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Today, BSNL is the No. 1 telecommunication company and the largest public sector undertaking of India and its responsibilities includes improvement of the already impeccable quality of telecom services, expansion of telecom services in all villages and instilling confidence among its customers.
Apart from vast network expansions, especial emphasis has given for introducing latest technologies and new services like I-NET, INTERNET, ISDN (INTEGRATED SERVICES DIGITAL NETWORK), IN (INTELLIGENT NETWORK), GSM and WLL (WIRELESS IN LOCAL LOOP) services etc. Now BSNL has also entered in mobile communication. BSNL has all the new services send technological advantages, which are available with any well, developed Telecom network anywhere else in the country.
Full credit for all above achievement goes to the officers and staff of the BSNL. The administration is fully aware of the challenges lying ahead and quite committed to provide the latest and best telecom services by their continued support and active co-operation.
When it comes connecting the four corners of the country , and much beyond , one solitary name lies embedded at the pinnacle- BSNL. A company that has gone past the number games and the quest to attain the position of the leader. It is working round the clock to take India in to the future by providing excellent telecom services for people of India.
Driven by the very best of telecom technology from global leaders, it connects each inch of India to the infinite corners of the globe, to enable you to step in to tomorrow.
The telecom services have been recognized the world over as an important tool for socio-economic development for a nation and hence telecom infrastructure is treated a crucial factor to realize the socio-economic objectives in India. Accordingly the Department of Telecom has been formulating developmental policies for the accelerated growth of the telecommunication services in various cities. The department is also responsible for frequency management in the field of radio connection in close coordination with the international bodies.
MAKING A TELEPHONE CALL
A telephone call starts when the caller lifts the handsets of the base. Once the dial tone is heard, the caller uses a rotary or a push button dial mounted either on the handset or on the base to enter a sequence of digits, the telephone number of called party. The switching equipment from the exchange removes the dial tone from the line after the first digit is received and after receiving the last digit, determines the called party is in the same exchange or a different ones. If the called is in the same exchange, burst of ringing current is applied to the called party’s line. Each telephone contains a ringer that responds to specific electric frequency. When the called party answers the telephone by pocking up the handset, steady start to flow in the called party’s line and is detected by the exchange. The exchange than stops applying ringing and sets up the connection between the caller and the called party. If the called party is in different exchange from the caller, the caller exchange set up the connection over the telephone network to the called party’s exchange. The called party then handles the process of ringing, detecting an answer, and notifying the calling and billing machinery when the call is completed. When conversation is over, one or both parties hang up by replacing their handset on the base, stopping the flow of current. The exchange when initiates the process of taking down the connection, including notifying billing equipment of the duration of the call if appropriate.
ABOUT THE EXCHANGE
All telephone subscribers are served by automatic exchanges, which perform the functions the human operator. The number being dialed is stored and then passed to the exchange’s central computer, which in turns operates the switching to complete the call or routes it a higher level switch for further processing. Today’s automatic exchanges uses a pair of computers, one running the program that provides services and the second monitoring the operation of the first, ready to take over in a few seconds in the event of equipment failure.
Various exchanges present in BSNL are:
All exchange has some purposes and some basic structural units, which are:
1. subscribers connection unit
2. switching network (CX)
3. control unit
For smooth working of an exchange following unit are very important:-
1. Computer Unit
: - it deals with additional services of the exchange to the customers with the help of computers.
2. Power Plant
:- to feed proper power supply to exchange
3. AC Plant
: - to maintain the continuous temperature + or – 2 degree Celsius to the digital switch (exchange).
: - to connect switch (exchange) with the external environment (subscriber) i.e. it is the interface between subscribers and exchange.
As the name specified it is the main part of the exchange that deals with the all services provided by the exchange to the customers with the help of computer. It also provides the updated data to all other part of the exchange.
The customers are using the services of the exchange by using the internet also gets connected to the main server present this room via an internet room.
It mainly consists of the servers that are providing the different services. The main servers of this room are:-
is used for the change number services provided by the exchange.
are provided by the exchange to avoid the problems that the users are facing the repairing of telephone. In this system when the user enters it’s complained it gets directly entered to the server and user is allotted with an id number.
LOCAL DIRECTORY ENQUIRY
is another services provided by the exchange, by using this; subscribers calls the particular number and gets the directory enquiry. The server present in the main computer room provides this service.
INTERNET DIRECTORY ENQUIRY
is the latest service by the exchange. In this type of service makes it enquiry using the internet, which gets connected to the main server at the internet room in the exchange and further to the main server in the computer room.
As we know that, the power is the main source or any organization. It is the case of E-10B exchange. That is the first requirement of any organization is the input.
The main source of this exchange is AC supply. However, as soon as the power supply is gone off, then what is source? No one think on this that the telephone is always plays its role in the human life. Even if the power supply gone off. Thus there must be adjustment source of power.
The main parts of the power room are:
Batteries: - these are the instant sources of the power as soon as power is gone off.
UPS (Uninterrupted Power Supply):- the UPS must give supply to the computer. As we know there is some equipment which can withstand any type of power supply, but there are also some instruments which cannot withstand with this type of power supply, even a microsecond delay will cause the loss of data.
Charging- Discharging Unit: - the batteries we are using in the power room need timely charging. As soon as the AC power supply is on, we make use of the charging unit present in the power room. The slowly charging of the batteries is known as the trickle charging. But sometimes we need the BOOSTER charging. In this type of charging awe take of the batteries from the load and charge separately, until it gets fully charged.
The main work of the discharging unit is to control the discharging of the batteries.
Inverter and Converter Unit: - the main use of this system is to change AC mains to DC and vice versa as required by the parts of exchange.
Engine Room:-we know that the batteries are the instant source of supply but we cannot use it for much larger time, thus for this, we have an engine to generate the power supply. They are of 885 KVA. Thus, this room controls the supply of the engine.
CENTRAL AIR CONDITIONER
For the function of electrical equipment, cooling system is basic requirement. The basic advantages of cooling systems are following-
It provides the thermal stability so that the temperature does not reach the tolerance limit of electronic equipment
It saves equipment from dust so to avoid malfunction of equipment’s.
It protects equipment from excess humidity which can caused rusting of equipment.
The basic unit of measurement used in the industry is known as “ton of refrigeration” (TR) which is equivalent to the heat extracted in 24 hours for converting thousands kg of liquid to ice at zero degree.
The compressor is the heart of the AC system and the costliest. It increases the pressure and temperature of the refrigerant gas coming from the evaporator coils by compressing it.
Compressor comes in various types. The most widely used is simple reciprocal type a cylinder and piston arrangement. For capacity more than 120 TR, centrifugal compressors are used. The condenser liquefies the refrigerant gas by a heat exchange process. The capillary tube or the expansion valve pressurizes liquid refrigerant and meters it flows to the evaporator.
The refrigerant then passes trough the evaporator coils, which extract heat out of the ambience.
MAIN DISTRIBUTION FRAME
The primary function of MDF is:
The fault of telephone number is removed in the MDF; it is called as Fault Remove Section.
For removing the fault of telephone number, we use the testing
These testing are T.T.Y. testing, Group testing, etc.
For any type of testing firstly we need the vertical no. or the live tester, printer and computer test N.E. number of that particular telephone number.
The telephone numbers are also disconnected in the MDF because of some specific reason.
ORGANISATION OF THE MDF
PARTS OF THE MDF
It is again subdivided in to two parts
Description of the horizontal side:-
: - On the rack, the tags are situated. One rack is having eight tags. The courting is done from up (0) to down (7).
: - Each rack consists of eight tags.
1 tag = 4 core
1 core = 4 bunch
1 bunch = 2 line
:- The word NE stands for the ‘NUMBER OF EQUIPMENT’.
It is a 128 pair cable. The EWSD and MDF connected by NE.
:-If we want to disconnect any two numbers then we insert a wedge between subscriber side and exchange side. Here wedge works as insulator made of plastic.
The vertical aside connected to the underground cable. This cable is having 100 pairs.
These pair is distributed when we allot the telephone number to the subscriber.
Vertical side is again subdivided in two parts:
One part is connected with the horizontal side and another with the subscriber line by using 100 pair underground cable.
This is how the present day telephone system works. Different exchanges have different architectures of switching call routing and other features.
Now let us see how BSNL has kept up with the changing world and provided the subscribers with the latest facilities technologies, which include the V-SAT network, Internet, the WLL (wireless in local loop) and the GSM mobile.
What is V-SAT?
It can be defined as a class of very small aperture Intelligent Satellite Earth Station suitable for easy on-premise installation, usually operating in conjugation with a large size HUB earth station. Capable of supporting a wide range of two ways integrated Telecom Services.
It has the following components:
Micro Earth Station
Mini Earth Station
Personal Earth Station
Roof Top Terminal
Customer Premises Terminal