TYPE - PUBLIC ESTABLISHED IN 1964 POWER GENERATION AND TRANSMISSION, INDUSTRY, TRANSPORTATION, RENEWABLE ENERGY, DEFANCE Over 150 Project construction sites in India & Abroad
NEW DELHI VADODARA NAGPUR PATNA KOLKATA VARANASI GOINDWAL HARIDWAR RUDRAPUR JAGDISHPUR JHANSI BHOPAL HYDERABAD BANGALORE RANIPET TIRUCHIRAPALLY CHENNAI CHANDIGARH VISAKHAPATNAM Registered Office & Corporate HQ : New Delhi 8 Service Centres 15 Manufacturing units 4 Power Sector Regional HQs Subsidiary-BHPV
Telecommunication is the assisted transmission of signals over a distance for the purpose of communication The term telecommunication is applied on the number of thing such as internet, mobile, satellite system, radio television, LAN and satellite phones Multiple transmitting and receiving. As no operator is required.
ELECTRONIC EXCHANGES Electronic devices effect the inter-connection between different transmission circuits and Electro-mechanical relays and switches Electronic devices remove difficulties associated with mechanical contacts There are some disadvantages of such systems for using mechanical contacts, due to following reasons. Advantage:- : no time is loosed in making a connection. : very high speed of operation is possible.
Electronic Exchanges are of two types : Tone type:In this type of exchange sine waves are used. There speed of dialing for a given number is more than that of Pulse type. 2. Pulse type:In this type of exchange square wave is used due to which the dialing speed is lesser. TONES USED IN MODERN TELEPHONY 1.Dial Tone 2.Busy Tone 3.Ringing Tone
* With wires i.e. Cables Wireless Microwave Links through Satellite Cable: Two types of Cables are used. They are: 1-Underground cables : 2-Overhead cables :
There are mainly two types of faults that often occur in the Exchange. These are basically Faults that occur from Line Faults that occur due to Instrument Faults that occur from Line : Break fault Loop fault Earth fault Problems that can occur due to line faults : 1. Subscriber can not dial a number. 2. Ring Trip i.e. connection from the exchange breaks after one ring. 3. False Ring 4. Low speech 5. One sided speech
Faults that occur due to instrument : 1.The number is not being dialed 2.One way speech 3.Receiver coil is faulty Problems that can occur due to line faults 1.Dial tone breaks after two or three rings. 2.Instrument circuitry faulty.
MAINTENANCE. The subject of maintenance of Automatic Telephone Exchange can be broadly divided under two categories: - 1. Prevention of Service Failures. 2. Location of Faults and their removal. Prevention of Service Failures can be done in following ways: - 1. Suitable design and adoption of suitable adjustment standards of the equipment parts. 2. Keeping the rooms dust free, maintaining temperature and humidity under tolerable limits using air-conditioners etc... 3.When faults occur in some parts of the exchange, they should be detected and removed as quickly as possible.
1.Telegraph 2.Telephone 3.Radio 4. Television 5.Internet