JNTU B.Tech II Semester Examinations,Telecommunication Switching Systems And Networks, Apr/May 2008
( Common to Electronics & Communication Engineering and Electronics &Telematics)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) Why is it necessary to keep the magnetic diaphragm in an earphone displaced
from its unstressed position? How is this achieved?
(b) What happens if the ratio ?/?0 is not very small in case of an earphone?
(c) Estimate the bandwidth requirements of a single satellite that is to support 20 million telephone conversations simultaneously. [8+4+4]
2. (a) What are the disadvantages of single stage networks and explain how they can
be overcome by adopting a multi stage network?
(b) Explain about complete SPC control software with block diagram. [8+8]
3. (a) What are the objectives of numbering plan? How are they classified?
(b) How international and national telephone numbering plan is defined and Give
telephone number structure? [8+8]
4. (a) Define blocking probability and explain why it is called as time congestion.
(b) An exchange is designed to handle 2000 calls during the busy hour. One day, the number of calls during the busy hour is 2200. What is the resulting GOS? [8+8]
5. (a) What are the functions of LCU? explain.
(b) With the help of a block diagram, explain the operation of UART Receiver. [6+10]
6. (a) Explain in detail Mesh, Ring, Star and Bus network topologies in detail .
What are its merits and demerits. 
7. (a) Explain ISDN architecture with a neat block schematics.
(b) What are the services of NISDN ? Explain ISDN channels and transmission
8. (a) Explain the format of STS 1 frame in details.
(b) What are the functions of STS- Multiplexes and add / drop multiplexers.
(c) Explain device layer relationship in SONET [6+6+4]