Diploma in Information Technology Module III (3) 2209/302
November 2009 series
Questions 1-3

(i) List four different forms of information that can be transmitted through a data communication system. (2 marks)
(ii) Describe the three essential elements of a typical data communication system. (6 marks)
(i) Compare and contrast filtering and sampling as applied in the pulse code modulation scheme. (4 marks)
(ii) An analog signal with a bandwidth ranging from 300Hz to 3000Hz needs to be modulated on a 60kHz carrier. Assuming an amplitude modulation scheme, calculate the upper and lower sidebands of the resulting signal. (4 marks)

A data transmission medium with a bandwidth of 3100Hz utilizes 4 bits per baud. By employing the Nyquist formula, determine the data rate for this channel. (4 marks)

(i) Identify four types of noise that contribute to transmission impairment. (2 marks)
(ii) Explain two limitations of the microwave transmission medium. (4 marks)
(i) Differentiate between physical and logical topologies in network design. (4 marks)
(ii) With the aid of a diagram, illustrate the utilization of a bridge and a router in a local area network. (4 marks)

Figure 1 illustrates a data frame transmitted through a specific communication medium. Use the diagram to answer the following questions:

(i) Identify the type of transmission mode employed by the system. (1 mark)
(ii) Outline two advantages of the identified transmission mode. (2 marks)

(i) Define the term "demultiplexer" in the context of data communication. (2 marks)
(ii) Figure 2 portrays two transmission media that employ different multiplexing schemes. Use the diagram to answer the following questions:
I. Determine the multiplexing scheme used by each of the transmission media. (2 marks)
II. Explain the operation of the multiplexing scheme represented in transmission media A. (4 marks)

Describe the functionality of ATM switches. (2 marks)

Manic Polytechnic is currently in the process of implementing a local area network to fulfill one of its objectives in the performance contract. The management is undecided between using bus or ring topologies.

(i) Provide two advantages and two disadvantages of each of the topologies under consideration by the management. (8 marks)
(ii) Justify your recommendation for the most suitable solution to the management. (2 marks)