Multiplexing is the process of combining multiple signals into one signal, over a shared medium.

i) The process is called as analog multiplexing if these signals are analog in nature.

ii) If digital signals are multiplexed, it is called as digital multiplexing.

Multiplexing was first developed in telephony. A number of signals were combined to send through a single cable. The process of multiplexing divides a communication channel into several number of logical channels, allotting each one for a different message signal or a data stream to be transferred. The device that does multiplexing, can be called as a MUX.


The reverse process, i.e., extracting the number of channels from one, which is done at the receiver is called as DE multiplexing. The device which does DE multiplexing is called as DEMUX.


The following figures illustrates the concept of MUX and DEMUX. Their primary use is in the field of communications.



Types of Multiplexers:-

                                               There are mainly two types of multiplexers, namely analog and digital. They are further divided into FDM, WDM, and TDM. The following figure gives a detailed idea about this classification.