Audio and video signal transmission over three twisted wire pairs

A system, apparatus and methods for transmitting video and audio data over twisted wire pairs are described. A differential signal that contains video colour information is transmitted over each twisted pair. Data representing digital samples of an audio signal is transmitted on two or more of the twisted pairs as a common mode signal. The audio data may be transmitted using balanced common mode signalling by applying a positive signal to a first twisted pair and a negative signal of equal magnitude to a second twisted pair. The data representing digital samples of an audio signal may be transferred using a clock signal and a data signal.