1. Explain the three types of communication and give a practical example of each
    (i) Simplex transmission is always one way

    (ii) Half-duplex data transmission - data can be transmitted in both directions on a signal carrier, but not at the same time

    (iii) Full Duplex Transmission - transmission of data in two directions simultaneously
  2. Twisted pair cabling is a cost effective form of flood wiring explain what makes it so useful and its properties
  3. Explain what the term 10 base 5 mean and with what does it refer to
    The name derives from the fact that the maximum data transfer speed is 10 Mbps, it uses baseband transmission, and the maximum length of cables is 500 meters
  4. With the aid of diagrams explain the three types of fibre optic cabling currently in use
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  5. Explain what is meant by Baud rate and its effect on the data transfer rate over a filtered bandwidth
  6. RS232 is a standard for asynchronous communications give the maximum data transfer rate, distance and explain what the value 2500pF has on these values
  7. With the aid of a diagram explain the process of odd parity as used in asynchronous data transfer
  8. Explain with the aid of a diagram the process of block checking
  9. With the aid of a diagram explain how does RS422 decipher the data on the transmission line
  10. Given the binary code 11011000102 draw the RTZ output
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  11. Given the binary code 11011000102 draw the Manchester encoding output
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  12. Explain the rules of HDB3 with regards to the violation and balancing pulses
  13. The HDB3 code replaces any instance of 4 consecutive 0 bits with one of the patterns “000V” or “B00V”
  14. With the aid of diagrams explain the processes of ASK & FSK
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  15. Explain the differences between coherent and differential PSK include any advantages and disadvantages
    The difference between Coherent and Differential PSK is Coherent PSK adds a 180 degrees phase shift to the carrier be it an “1” or a “0” whilst the Differential PSK adds a phase shift to every bit whether a transition or not with 90 degree being a “1” and 270 degree being a “0”
  16. Explain the difference between data signalling rate and data transfer rate
    The difference is that the DSR is the real bit rate of the line including overheads whilst the DTR is the net bit rate and does not include overheads
  17. Given a bandwidth of 3400Hz and a modulation scheme of QAM 16 calculate the bit rate of the link and the signal to noise ratio in dBs of the link
    using the formula Wlog2 (SNR + 1)
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