In telecommunication, a carrier system (loosely, a synonym with carrier) is a multichannel telecommunications system in which a number of individual circuits (data, voice, or combination thereof) are multiplexed for transmission between nodes of a network.

In carrier systems, many different forms of multiplexing may be used, such as time-division multiplexing and frequency-division multiplexing.

Multiple layers of multiplexing may ultimately be performed upon a given input signal; i.e., the output resulting from one stage of modulation may in turn be modulated.

At a given node, specified channels, groups, supergroups, etc. may be demultiplexed without demultiplexing the others.

Source: from Federal Standard 1037C and from MIL-STD-188

See also: common carrier,Channel access method