Gujarat University
MCA Semester IV
Networking Technologies I
Date: 18th July, 1998 Marks: 50
Instructions:
1.Answer each section in separate answer books.
2. Figures to the right side indicate the total marks of the questions.
3. Assume suitable data wherever needed.
Section I
Q-1 Answer the following questions: [9]
1. What is channel capacity? How is it related to bandwidth?
2. How is the electromagnetic spectrum divided into various bands? Explain briefly the important characteristics of propagation of the electromagnetic waves in their frequency band. Which band is usually used for satellite communication? Why?
3. Explain the SDLC protocol in details with an example.
Q-2 Answer the following questions: [8]
1. Explain different types of modulation with diagram.
2. Explain TDM with a suitable example. Why TDM is the most preferred multiplexing technique in data communication?
OR
Q-2 Answer the following questions: [8]
(a) 1. What does the term “multidrop communication” mean? Where is multidrop communications needed?
2. Compare RS-423 to RS-232 in terms of bit rate, distance, single ended versus differential singles, number of users and voltages.
(b) What is noise? Classify noise giving the frequency distribution of the noise in each case. Also describe
the methods that may be used to alleviate the ill effects of noise on a data communication system.
Q-3 Answer the following questions:
(a) What are the advantages of Digital a Communication system over an analog communication system?
[2]
(b) Why is encoding used in data communication system? Explain any two encoding techniques with timing
diagrams. [2]
(c) Explain the multiplexing and Modulation of digital signals. [2]
(d)A system is designed to sample analog signals. Convert them to digital form with a 4-bit A/D converter
and transmit the data through a data channel. What should be the channel capacity if the sampling rate is to 10 kHz? [2]
OR
Q-3 Answer the following questions:
1. Explain the functions of SLIC. [3]
2. Describe the standards used for MODEM. [5]
Section II
Q-4 Answer the following questions:
a. What is the role of the Receiver and the Driver ICs in an RS-232 interface. [2]
b. Why different numbers of handshaking signals are needed in different application? Explain giving
appropriate example. [2]
c. A CRC checksum is used with 16 bits of CRC per 128 bits of data. What percentage of overhead does the
CRC add to the system? Repeat for a parity bit used with the same 128 bits divided into 16 bytes.
[2]
d. What are the IEEE 802.4, 802.4 and 802.5 standards? [2]
Q-5 Answer the following questions:
a. Compare Synchronous and asynchronous data communication systems giving suitable an example.
[3]
b. Describe the function of each one of the layers of the OSI model. [5]
OR
Q-5 Answer the following questions:
a. Explain any three basic network protocols. Compare them one another and give one area of application for each one of the protocols, you describe. [3]
b. In an RS-232 system, what are ‘break’ and ‘break’ detect? Why are they needed? [2]
c. Describe the following error condition in RS-232 system: Framing, Overrun & Parity error. [3]
Q-6 Write short notes on any three of the following: [9]
1. Cellular networks and systems
2. Current loop based data communication
3. ISDN
4. Fiber Optic Communication
5. Internet
