Acronym for 2 Binary 1 Quaternary.
2B1Q is a full duplex physical layer encoding method, used in ISDN, HDSL and SDSL.
Two binary bits are encoded into one quaternary signal, which doubles the effectiveness of transmission.
|Bits|Quaternary Symbol|Voltage Level |00|-3|-2.5 |01|-1|-0.833 |10|+3|+2.5 |11|+1|+0.833
See also: Binary, Ternary, Quaternary.
