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Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) Explain the principle operation of a four wire circuit with neat diagram.
8 M
1 (b) Express the following power levels in dBm and dBw. i) mW ii) 1w iii) 2 mW iv) 100mW.
4 M
1 (c) Explain the PCM primary multiplex with neat diagram, (30 channel or 24 channel frame format any one).
8 M

2 (a) Write a short note on crossbar system.
6 M
2 (b) With a neat block diagram, explain the term BORSCHT.
6 M
2 (c) With the help of a neat diagram, explain the Intra LM call and Inter LM call processing.
8 M

3 (a) Define the following terms (any three):
i) Traffic intensity ii) Grade of Service (GOS) iii) Busy hour iv) Blocking probability v) Blocking network.
6 M
3 (b) In an average, during the busy hour a company makes 180 outgoing calls of average duration of 3 minutes. It receives 400 incoming calls of average duration 6 minutes, Find:
i) The outgoing traffic ii) Incoming traffic iii) Total traffic
4 M
3 (c) Derive an expression for iterative form of Erlang's LOST CALL FORMULA with explanation of assumptions made.
10 M

8 M
4 (b) Compare the features of single stage and multi stage network.
8 M
4 (c) Design a grading for 16 outlet using switches with 10 outlets. Draw grading diagram.
4 M

5 (a) Explain the principle operation of T-S-T network and S-T-S network.
12 M
5 (b) Network has 50 incoming and 50 outgoing PCM highway. Each conveying 40 channels. The required grade of service is 0.7 Find the traffic capacity of network mode (1) and mode (2).
8 M

6 (a) Explain the basic software architecture of a typical digital switching system.
10 M
6 (b) What is a feature flow diagram? Explain with flow charts.
10 M

7 (a) Explain the methodology used for reporting and correcting of field problems.
10 M
7 (b) Explain the strategy used for improvement of software quality.
10 M

8 (a) With a neat flow chart explain the simple call establishment process.
12 M
8 (b) Write short notes on any two of the following:
i) Reliability analysis
ii) Recovery strategy.
iii) Network Control Processor (NCP).
8 M

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