23B+D

Synonymous with primary rate interface (PRI). Referring to the ITU-T specification for an ISDN interface supporting 23 bearer (B) channels and 1 data (D) channel. 23B+D is compatible with T1 and J-1, and is used in North America and Japan. See also ISDN and PRI. 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 Baseband Digital Signal 2B1Q Line Coding +3V +1V 0V -1V -3V