A bit signaling procedure used in most T1 transmission facilities where one bit from every sixth frame of each of 24 T1 subchannels is used for carrying supervisory signaling.[What does it stand for? Is this the same as "bit robbing"?]
Last updated: 1997-05-05
AAUI ♦ A&B ♦ abbrev ♦ Abbreviated Test Language for Avionics Systems
Try this search on Wikipedia, Wiktionary, Google, OneLook.