NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
SEPTEMBER 2020 EXAMINATION

COURSE CODE: CIT 303

COURSE TITLE: PRINCIPLES OF COMMUNICATION TECHNOLOGY

CREDIT: 3 UNITS

TIME ALLOWED: 2½ HOURS

INSTRUCTIONS: ANSWER QUESTION ONE (1) AND ANY FOUR (4) OTHERS

QUESTION ONE (22MARKS) COMPULSORY

a. Discuss the effectiveness of data communication system with reference to delivery, accuracy, timeliness and jitter. 4marks

b. Explain the concept of “performance and reliability” as basic criteria in a network communication system. 4marks

c. Suppose a user X in Lagos want to make (point-to-point) phone call to user Y in the Company Office’s in Abuja. Describe the procedures required to establish and make the call. 4marks d. Explain the key element of protocols in computer networks. 3marks

e. Distinguish between Shift Cipher and Transposition Cipher. 3marks

f. Given a key using a block of four characters as: Plaintext: 2 4 1 3 Ciphertext: 1 2 3 4 Decrypt the message “XMEANTIAOTIN” using transposition cipher technique using transposition cipher technique. 4marks

QUESTION TWO (12MARKS)

a. Use schematic diagrams to illustrate point – to – point and multipoint connections. 4marks

b. Explain any 2 means in which the Media Access Control Sublayer determines where one frame of data ends and the next one begin. 4marks

c. Explain any 2 basic functions of the Data Link Layer. 4marks

QUESTION THREE (12MARKS)

a. List any five advantages of the TCP/IP Model. 4marks

b. (i) State any 4 characteristics of IP 2marks

(ii) Explain the term “IP addressing” 2marks

c. Distinguish between Analog and Digital Signals 4marks.

QUESTION FOUR (12MARKS)

a. State the 3 categories of wireless transmission. 3marks

b. Despite current achievement to handle voice and video services over the internet, service delivery is still a measure concern. What are some of the critical changes that must be put in place to change this narrative? 5marks

c. In Time and space domain, what is the use of filtering. 4marks

QUESTION FIVE (12MARKS)

a. Describe the OSI layer that is closet to end user. 6marks

b. Explain any two implementations that can be done at the presentation layer. 6marks

QUESTION SIX (12MARKS)

a. In Time and Space domain, what is the use of filtering. 4marks

b. Explain any two types of filter characterization. 4marks

c. Give any 4 advantages of optical fiber. 4marks