Return-to-zero

Return-to-zero (RZ) describes a line code used in telecommunications signals in which the signal drops (returns) to zero between each pulse. This takes place even if a number of consecutive zeros or ones occur in the signal. This means that a separate clock does not need to be sent alongside the signal. The signal is self-clocking. A variant, Return-to-zero, inverted, swaps the signal values for one and zero.