Explaination
- Where the network user devices are wholly digital, analogue wave forms cannot be used. Instead, the communications medium carries two discrete signals which in turn correspond to binary values 1 and 0.
For example, a voltage of +12 volts can represent the binary value 1 and a voltage of -12 volts can represent the binary value 0, This can be illistrated by the square waveform of a digital signal.
Optical fibre, which is now widely used for digital communications, uses pulses of light rather than electricity to represent binary data (light =1, no light =0).
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