Comp 222-Telecommunications And Computers Question Paper
Comp 222-Telecommunications And Computers
Course:Bachelor Of Computer Science (It Telecommunication)
Institution: Kabarak University question papers
Exam Year:2009
KABARAK UNIVERSITY
UNIVERSITY EXAMINATIONS
2009 ACADEMIC YEAR
FOR THE DEGREE OF BACHELOR OF SCIENCE IN
COMPUTER SCIENCE
COURSE CODE: COMP 222
COURSE TITLE: TELECOMMUNICATIONS AND
COMPUTERS
STREAM: Y2S2
DAY: TUESDAY
TIME: 2.00 – 4.00 P.M.
DATE: 04/08/2009
INSTRUCTIONS:
1. Answer Question ONE and any other TWO questions.
2. Question ONE carries 40 marks. Questions TWO – FOUR carry 15 marks each
QUESTION ONE (30 Marks)
a) Briefly define a network.
(3 marks)
b) Identify the at least two of the basic components of a data communications system.
(2 marks)
c) Briefly describe the functions of the transport layer in the OSI model.
(4 marks)
d) What is the bandwidth of a signal that has frequencies ranging from 50 KHz to 5
MHz?
(2 marks)
e) An analog signal carries 6 bits in each signal unit. If 1000 signal units are sent per
second, find both the baud rate as well as the bit rate of the signal.
(4 marks)
f) Briefly differentiate between the operations of Ethernet and token ring networks.
(8 marks)
g) Name at least three characteristics which are specified in the RS-232 standard.
(3 marks)
h) Why is the Asymmetric Digital Subscriber Line (ADSL) service provided by
telephone companies called asymmetric and why is it not very suitable for corporate
clients?
(4 marks)
QUESTION TWO (20 MARKS)
a) The figure below represents the Manchester encoding of a certain data stream. What
is the data stream?
(6 marks)
b) Differentiate between the following methods of error detection in data transmission;
i. parity check
ii. checksum
iii. cyclic redundancy check
(9 marks)
c) A signal with a bandwidth of 60 Hz is made up of 10 different waves. The highest
frequency in the signal is 100 Hz.
i. Determine the lowest frequency in the signal
ii. Draw the frequency spectrum of the signal, assuming the frequency gaps
between the different waves is equal and all have the same magnitude.
(5 marks)
QUESTION THREE (20 MARKS)
a) According to Nyquist’s theorem, what sampling rate is required for a signal whose
bandwidth ranges from 1000Hz to 15000Hz?
(4 marks)
b) With the aid of diagrams, show how you would connect a hybrid topology with a bus
backbone connecting two ring backbones. One of the ring backbones connects four
star networks of five nodes each while the other one connects five nodes.
(10 marks)
c) Differentiate between serial and parallel data transmission modes and give one
advantage of each transmission mode.
(6 marks)
QUESTION FOUR (20 MARKS)
a) Name the main categories of multiplexing used for transmission of signals. For each
category, describe briefly how it is implemented.
(12 marks)
b) Differentiate between low-pass and band-pass transmission media and state which
one is preferred for analog transmissions and which one is preferred for digital
transmissions. Give an example of when a cable such as coaxial can be used to
transmit data digitally.
(8 marks)
QUESTION FIVE (20 MARKS)
a) Name the three main types of unguided media used in telecommunications. For each
category, state the following;
i. mode of propagation
ii. frequency ranges
iii. two applications
(12 marks)
b) Find the minimum bandwidth for an FSK signal transmitting at 2 kbps. Transmission
is in half-duplex mode and the carriers are separated by a gap of 3000 Hz.
(4 marks)
c) Convert the decimal number 115 to its equivalent in
i. binary
ii. hexadecimal
(4 marks)
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