To multiplex or combine several data streams or signals for transmission on a shared communications channel.

Multiple data streams or signals may be combined at the transmitter by a multiplexer or mux and separated at the receiver by a demultiplexer or demux.

The communications channel may be shared between the independent signals in one of several different ways: time division multiplexing, frequency division multiplexing, or code division multiplexing.

In MPEG digital encoding, multiple elementary streams of audio, video or associated data can be combined or multiplexed to form a single transport stream. A mux file is a data file in which multiple streams have been multiplexed or combined in such a manner.

In digital video broadcasting a multiplex or mux may refer to a group of signals encoded in a single transmission channel and may contain several traditional television channels.