NRZ-L: [Non-Return-to-Zero-Level] In NRZ-L encoding, the polarity of the signal changes only when the incoming signal changes from a one to a zero or from a zero to a one. NRZ-L method looks just like the NRZ method, except for the first input one data bit. This is because NRZ does not consider the first data bit to be a polarity change, where NRZ-L does.

NRZI [Non-Return-to-Zero-Inverted Encoding] A '0' is encoded as no change in the level. However a '1' is encoded depending on the current state of the line. If the current state is '0' [low] the '1' will be encoded as a high, if the current state is '1' [high] the '1' will be encoded as a low. Used with FDDI and USB for example.

Bipolar-AMI Signal Encoding A multilevel binary approach in which binary 0 is represented by a lack of pulse, and a binary 1 is represented by a positive or a negative pulse. The binary 1 pulses must alternate in polarity. Each 1 introduces a transition that can be used for synchronization

Manchester Signal Encoding Manchester encoding is a biphase encoding in which the transition takes place in the middle of the bit period: a low-to-high transition for 1, and a high-to-low transition for 0.

Differential Signal Encoding A biphase encoding in which transition at the start of the bit period represents 0, and a lack of transition at the start of the bit represents 1. In addition, a transition occurs at the middle of each bit period just for the purpose of clocking.