Communication System

There is disclosed a method and apparatus for recovering data from a received signal, the received signal including a first signal comprising data bits and a second signal having transitions at data bit boundaries of the first signal where there is an absence of transitions, the method comprising: receiving the first signal; receiving the second signal; sampling the first signal to detect an edge transition of the first signal; sampling the second signal to detect an edge transition of the second signal; wherein on an active edge of either said first or said signal, the current value of the first signal is recovered as a received data bit.