Abstract: A multi-channel trellis encoder/decoder is disclosed for use with multi-channel data transmission systems. For each data transmission symbol interval, trellis encoding is applied across all available channels, and for each data reception symbol interval trellis decoding is applied across all available channels. In comparision with systems employing independent trellis encoding along each available channel, the present invention reduces data throughput delays by roughly an order of magnitude, and reduces implementation complexity by roughly a factor equal to the number of transmission channels. Further, the multi-channel trellis encoder will permit different data transmission rates as well as permitting variations in signal power and/or noise power from channel to channel.