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Chapter 7 NETWORKS

COMMUNICATIONS
  1. Study figure 7.1 and the notes beside it. Make a list of the devices that can be termed ”Sending and Receiving Devices”

  * Personal computers.
  * Notebook computers/ laptops.
  * Web-enabled cellular telephones/ 3G
  * WebTV
  * GPS receivers
  * TabletPC’s
  * Mid-ranged servers

  2. Make a list of elements that make up “Communications Channels”

  * Telephone lines
  * Underground cables
  * Microwave stations
  * Earth stations
  * Satellites

  3. What is the function of a modem?

Convert or format signals so that they are suitable for the communications channel or receiving   device. When using a telephone line, the modem needs to convert between analogue and digital.

  4. Dial up modems provided a maximum bandwidth of 56 Kbps.   What broadband technologies have replaced dial up modems?

  * XDSL
  * Cable Modem
  * Satellites

  5. What does ADSL stand for? Explain what communication channel ADSL uses and explain how it is different to a dial up modem communication?

Uses the same telphone line as dialup, but by changing the frequency of the signal, ADSL technology is able to demodulate digital signals over reasonable distances.

  6. Explain Cable Broadband – what communication channel does it use?

A cable channel uses coaxial cables that Pay TV companies have deployed in urban areas. These cables used to deliver TV signals are able to carry digital signals faster.

  7. Explain Satellite Broadband – where would you expect it to be used?

A dish is placed at the client’s house whereit can exchange signals with a nearby microwave earth station which has the capacity to interact with orbitting satelltes.
NETWORKS
  8. What is a network?

A collection of computers and devices by communications channels that facilitate the sharing of data, software programs and internet services.

  9. Summarise the 5 main advantages of using a network over... [continues]

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