Data communication system having channel switching means

摘要

A data transmission system comprising a transmit unit 2 having a buffer 22 for generating a delayed version of the transmitted data signal and the receive unit 4 comprising a buffer 47 for generating a delayed version of the received data signal, error detection means for detecting errors in the received data signal and means for signalling the transmit unit 2 to transmit the delayed version of the transmitted data signal.