Rashtrasant Tukadoji Maharaj Nagpur University 2011 B.E Electronics & Communication Engineering Faculty of Engineering and Technology, LINE COMMUNICATION AND SWITCHING SYSTEM - Question Paper

part A
1. (a) Compare the advantages and disadvantages of Morse code with 5-units code.
(b) elaborate advantages that can be found by clamping the armature of polarized relay? Justify your conclusion.
(c) If the smallest element in a telegraph code is 20msec, compute the speed in baud, character per 2nd and words per minute in: Morse code, Cable code, five unit code and 7.5 unit Teleprinter code.

2. (a) discuss the subsequent terms:
(i) Simplex
(ii) Duplex
(iii) Differential Diplex
(iv) Bridge Duplex
(b) discuss with neat sketch the principle of operation of Morse Sounder.

3. (a) How does a telex subscriber know:
(i) That he has been connected to the identical subscriber.
(ii) That the called subscriber is busy.
(iii) That the subscribers line is open for a few other defect.
(iv) That he has got a wrong number.
(b) define with the help of neat diagram a Teleprinter receiver.

4. (a) elaborate the functions of transmission bridges? elaborate the different transmission bridges that obtain use in telephony? define any 1 with circuit diagram.
(b) define the method of signalling as employed in a telex network for the establishment of local calls.

5. Write short notes on (any three):
(i) Fascimile
(ii) Telegraph Repeater.
(iii) Budget multiplex.
(iv) Telephone Receiver.

part B
6. (a) Compare and contrast the manual and automatic exchanges.
(b) Draw and discuss the trunking diagram of a 1000 line exchange.
(c) discuss the terms of applied to unselector mechanism.
(i) Driving magnet
(ii) Interrupter Contacts
(iii) Bank Contacts
(iv) Wiper assembly

7. (a) For how many minutes during the busy hour is a single selector engaged if it carries an avg. traffic of 0.75 erlangs?
(b) discuss the subsequent terms used with selectors of an auto exchange:
(i) Guarding
(ii) Hunting
(iii) Finding
(iv) Testing
(v) Holding

8. (a) elaborate the objectives of Cellular Telephony?
(b) discuss the concept of ISDN. How are the various systems transmitted over the identical channel? discuss with neat sketch.

9.(a) discuss in detail cross bar exchange.
(b) Write the advantages and disadvantages of power line carrier.

10. Write short notes on (any three):
(i) BORSCHT Function
(ii) SLIC
(iii) Long that carrier telephone system
(iv) Electronic Switching system.

Earning:   Approval pending.