In communications, a device that breaks up a high-speed transmission into several low-speed transmissions, and vice versa. It is used to transmit LAN and videoconferencing traffic over lower-speed digital channels. For example, to transmit Ethernet over a T3 link, the 10 Mbps Ethernet channel would be inverse multiplexed into multiple 64 Kbps channels of the T3 line. A 336 Kbps videoconferencing transmission could be split into six 56 Kbps channels to transmit over a Switched 56 service. Contrast with multiplexor.