unit 8 communication technology

Authors Avatar

BTEC NATIONAL (CERT) FOT ICT PRACTITIONERS                                                                             UNIT 8

Communication Technology

Task 1 – Signal Theory

Byte – byte is a term used for the unit which computer storage is measured in, 1 byte consists of 8 bits, a kilobyte (or 1 KB) consists of 1024 bytes. A megabyte (1 MB) consists of 1024 KB. A gigabyte consists of 1024 MB.

Synchronous & Asynchronous Data Transmission – these are two ways which are used to regulate the sending of data. Like always for more than one device to communicate there must be a signal which synchronises the transmission on receipt of data which is called the clocking signal. So when both devices send and receive suing the same clock signal, they communicate and transfer data accurately. The second device asynchronous is used to refer systems to communicate one way on demand as it is without clocking such as a computer to a printer.

Task 2 – Methods of Communication & Protocols

Simplex – this is when communication is only one way, for example from a computer to a printer, as the printer doesn’t send data back to the computer this is known as simplex and it is only in need of one serial lane.

Half Duplex –this is when two devices can communicate through the same lane but not at the same time, for example when a computer is sending data to the USB drive then at that moment of transmission the USB drive can not send anything back until the transmission from the computer is finished.

Duplex –this is when communication can take place from both ends at the same time, so in other words, you can send and receive at the same time, for example, mobile phones, when you call someone, both callers can speak at the same time.

USB –the USB is a means of communication when plugged in the computer, it’s a way to save data onto the USB, or there are other resources that use USB for example, wireless internet on a laptop, when you connect the USB which you got from the service provider and you plug it in, once plugged in you are connected to the internet, USB is also used for other resources, such as connecting mobile phones to computer and also connecting digital cameras, etc.

Task 3 – Communication Protocols


  • Allows users to connect with their pc or laptop without the need of being wired into a socket
  • Creates portable network centers which can be taken anywhere on the globe
  • Serves to enhance the range of the network so that a connection could be made from those unreachable places where it may be too expensive to run cables
  • Narrowband sends a signal over a frequency range which is limited
  • Spread spectrum uses range of techniques & frequencies
  • 802.11 and 802.11a operates at speeds of up to 6mbits per second
  • 802.11b operates at a speed of 11mbits per second and is commonly used for wireless networking at school, home, office or a small business
  • 802.11g is similar to the range of Bluetooth but with more power as it can work at a speed up to 54mbits per second, and operates in the 2.4GHz
Join now!


  • Ratified as
  • Added support for non-encrypted channels.
  • Received Signal Strength Indicator ().
  • Extended inquiry response
  • Bluetooth Radio
  • Higher transmission speeds in practice, up to 721kbit/s, as in 1.1.
  • Extended Synchronous Connections (eSCO), which improve voice quality of audio links by allowing retransmissions of corrupted packets, and may optionally increase audio latency to provide better support for concurrent data transfer.


  • Devices connect by searching
  • Operates I the 900 or 1800mhz bands
  • The transmission power in a handset is limited to ...

This is a preview of the whole essay