A system and method is disclosed for adding a low data rate data channel to a 100Base-T Ethernet link without significantly impacting an IEEE defined 100Base-T protocol for the Ethernet link. A dual data channel transmitter encodes a high data rate data stream in an MLT-3 encoder and encodes a low data rate data stream using bit representations that are not valid bit representations in the MLT-3 encoder. The dual data channel transmitter transmits both of the encoded bit streams in a dual data stream. A dual data channel receiver receives the dual data stream and separates and decodes the two bit streams. A low data rate data channel is provided in conjunction with a high data rate data channel without significantly impacting the operation of the high data rate data channel.