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. Note 1: In carrier systems, many different forms of multiplexing may be used, such as time-division multiplexing and frequency-division multiplexing. Note 2: 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. Note 3: At a given node, specified channels, groups, supergroups, etc. , may be demultiplexed without demultiplexing the others. Synonym carrier.