Communication timing coordination techniques

A communication unit ( 30 ) arranged to send transmit data includes a receiver ( 32 ) arranged to recover input data transmitted at a downstream transfer rate in response to a symbol clock ( 20 ) signal. A transmitter ( 40 ) is arranged to transmit the transmit data at an upstream transfer rate in response to an upstream transmit clock signal (TX_CLKA) that is coordinated with the symbol clock signal. The frequency or repetition rate of the upstream transmit clock signal is defined at least in part by a predetermined relationship between the downstream transfer rate and the upstream transfer rate, such as a ratio of the downstream transfer rate and the upstream transfer rate.