CIT303 : PRINCIPLES OF COMMUNICATION TECHNOLOGY (2014)

NATIONAL OPEN UNIVERSITY OF NIGERIA

14/16 AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS

SCHOOL OF SCIENCE AND TECHNOLOGY

MARCH/APRIL 2014 EXAMINATION

 
COURSE CODE: CIT 303
COURSE TITLE: PRINCIPLES OF COMMUNICATION TECHNOLOGY
TIME ALLOWED: 3HOURS
INSTRUCTION: ATTEMPT ANY FIVE (5) QUESTIONS
 
Question 1
a.       Encrypt the word “IGNORANCE” with the following ciphers:
i.      Shift cipher  with key=1                                     (1 mark)
ii.      Shift cipher with key= 26                      (2 marks)
iii.      Shift cipher with key=0                         (2 marks)
iv.      Transposition cipher where plain text: 1 2 3 4 5 6 7 8 9   and
cipher text: 4 3 1 5 2 6 7 9 8 (with no bogus character)                         (1.5 marks)
 
b.       Decrypt the word “ANCEIGNOR” with the following ciphers:
i.          Shift cipher  with key=1                                 (1 mark)
ii. Shift cipher with key= 26                      (2 marks)
iii.                   Shift cipher with key=0                             (2 marks)
iv. Transposition cipher where plain text: 1 2 3 4 5 6 7 8 9   and
cipher text: 4 3 1 5 2 6 7 9 8 (with no bogus character)                         (1.5 marks)
 
c.        The   amplification   in   a   cable   is   usually   defined   in   decibels  per kilometer (dB/km). If the signal at the beginning of a cable with 2 dB/km has a power of 2 mW, what is the power of the signal at 5 km? (3 marks)
 
d.       Briefly explain the term attenuation (1.5 marks)
 
Question 2
 
.
a.       Define the term “network topology”. (1 mark).
b.      With the aid of diagrams, briefly explain the following network topologies:
i.  Ring (3 marks)
ii.      Mesh (3 marks)
iii.    Tree (3 marks).
c.       State and briefly explain 3 advantages and 3 disadvantages of using fiber optic cables in networking. (6 marks)
d.      State 1 advantage and 2 disadvantages of STP cables in comparison to UTP cables. (1.5 marks)
 
Question 3
 
a.       With the aid of a table ONLY, describe the five classes of IPv4 addresses under the following columns:            (10 marks)
i. IP Address Class
ii. Format
iii. Purpose
iv. Number of network/ host bits
v.      Max number of hosts
 
b.       Briefly explain each of the following terms:
i.      Linear filter       (2 marks)
ii.      Stable filter       (1 mark)
iii.      Unstable filter   (1 mark)
iv.      Time-invariant filter (1 mark)
v.      Adaptive filter              (1 mark)
vi.      Linearity (in the context of linear-time invariant (LTI) (1.5 marks)
Question 4
i)                    Outline four (4) basic Network Topologies.
ii)                   List three guided Media.
iii)                 In one sentence, describe the OSI reference model (1 mark)
 
 
Question 5
a.       Briefly explain the 3 modes of communication (with regards to the direction of communication). In each case, identify 2 examples of devices that utilize that mode of communication. (9 marks)
b.       State  the following:
i.  4 services/ functions provided by the  OSI Physical Layer         (2 marks)
ii. 4 services/ functions provided by the  OSI Data Link Layer (2 marks)
iii. 4 services/ functions provided by the  OSI Transport Layer (2 marks)
iv.3 services/ functions provided by the  OSI Session Layer           (2.5  marks)
 
Question 6
Contrast between:
i)             Analog Signal Processing
ii)            Digital Signal Processing
 
 
Question 7
 
a)      What is Data Communications?
 
b)      Define Protocols.
 
c)       The effectiveness of a data communications system depends on four fundamental characteristics. List and define these characteristics.
You can get the soft copy for this course (2014-till date) at a little token or the exam summary answers for this course from 08039407882

Exam summary sample below

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