Manchester code

In telecommunication and data storage, Manchester code (also known as phase encoding, or PE) is a line code in which the encoding of each data bit is either low then high, or high then low, for equal time. It is a self-clocking signal with no DC component. Consequently, electrical connections using a Manchester code are easily galvanically isolated.

Manchester code derives its name from its development at the University of Manchester, where the coding was used for storing data on the magnetic drums of the Manchester Mark 1 computer.

Manchester code was widely used for magnetic recording on 1600 bpi computer tapes before the introduction of 6250 bpi tapes which used the more efficient group-coded recording.^[1] Manchester code was used in early Ethernet physical layer standards and is still used in consumer IR protocols, RFID and near-field communication.