Glossary definition of Multiplexing

Multiplexing is a normal telecommunications technique, which enables multiple users or signals to share one communication channel or frequency band. The multiplex process is used to interleave the signals so that they appear to merge into one complex signal. A number of different multiplex systems are commonly used, the most familiar forms being Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM). The equipment that performs the multiplexing task is called a multiplexer, or mux.

At the receiving end of the transmission the original information is recovered by a de-multiplexer, which converts the interleaved signals back into separate signals. This system works because each individual signal (e.g. voice) only contains a small amount of information, in relation to the much greater bandwidth of the channel through which it passes. The multiplexing process is not noticeable to the user of the service.