Repeater is a network device that helps signals travel long distance over network.
A signals travel over long distance along certain medium. When signal travels then its intensity degrades and finally becomes distorted as it reaches its destination.
When a signals intensity degrades while travelling to its destination it is known as attenuation.
Due to attenuation the signals becomes unrecognizable when it reaches receiver. The repeater enables signals to travel longer distance over network. The repeater will regenerates the received signals and then transmits the received signals on other segments.
Repeaters are commonly used to extend a network cable.
All network cable standards have maximum cable length specification. If the distance between two devices is longer than this specification then repeater is needed to regenerate the signals. In absence of repeater, the signal reaching the receiver ends will be too weak to understand.
Repeaters can be of two kinds:
A LAN using a star topology with unsheilded twisted pair cabling is an example of the use of repeaters.
The length limit for unshielded twisted pair cable is 100 metres. The repeater amplifies all the signal that pass through it for length exceeding 100 metres limit.