Friday, March 25, 2011

Data Communications; Kenya National Examinations Council (KNEC) Questions

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

1.      (a)  (i) Outline four forms of information that can be transmitted through a data communication system. (2marks)
     (ii) Describe the three elements of a typical data communication system.        (6mks)
           (b) (i) Differentiate between filtering and sampling as applied in pulse code  modulation scheme. (4marks)

                  (ii) An analog signal with a bandwidth from 300Hz to 3000Hz is to be modulated on a 60khz carrier. Assuming amplitude modulation scheme, determine the upper and lower sidebands of the resulting signal. (4marks)
          (c) Adata transmission medium with a bandwidth of 3100Hz uses 4 bits per baud. Using the Nyquist formula, determine the data rate for this channel. (4marks)
2.      (a) (i) State four types of noise that constitute transmission impairment. (2mks)
            (ii) Explain two limitations of microwave transmission medium. (4mks)
      (b)  (i) Distinguish between physical and logical topologies as used in network design. (4maks)
             (ii) With the aid of a diagram, describe the use of a bridge and a router in local area network. (4maks)
     (c) Figure 1 shows a frame of data that is transmitted through a particular communication medium. Use it to answer the questions that follow.

(i)                  I dentify the type of transmission mode used by the system. (1 mark)
(ii)                Outline two advantages of the transmission mode identified in (i). (2maks)

3        (a) (i) Explain the term demultiplexor as used in data communication. (2 marks)
           (ii) Figure 2 shows two transmission media using different multiplexing schemes. Use it to answer the questions that follow.
I.                    State the multiplexing scheme used by each of the transmission media. (2mks)
II.                 Explain the operation of the multiplexing scheme represented in transmission media A. (4maks)
    (b) Describe ATM switches. (2mks)
    (c) Manic polytechnic is in the process of installing a local area network in order to meet one of its targets in the performance contract. The management is in dilemma of either using bus or ring topologies.
      (i) Outline two strengths and two weaknesses of each of the topologies the management is considering. (8maks)
       (ii) Suggest the most appropriate solution to the management justifying your answer. (2maks)

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i want a leaker? and pliz include other subjects, good work though.

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