ADTRAN 1202300L1, User Manual

Page: 45 / 54

Appendix B. Signalling States
61202300L1-1 FXS+ Quad Voice Option Module User Manual B-3
Tables B-3 through B-7 describe various modes for signal-
ling states.
The A and B signal bit states on the DS-1 signal are as fol-
lows:
Table B-3. FXS+ Mode (Loop-Start)
FXS+2W Input RX A RX B TX A TX B FXS+2W Output
(Outgoing call from FXS+)
Loop Open X 1 0 1 No Ringing (Idle)
Loop Closed X 1 1 1 No Ringing
Loop Closed X 1/0 1 1 Reverse Battery
(Incoming call to FXS+)
Loop Open X 0 0 1 Ringing
Loop Closed X 0 1 1 No Ringing
Signal Means
0 logic 0 is the DS-1 stream
1 logic 1 is the DS-1 stream
1/0 logic 1 followed by a logic 0 in each
successive signalling frame.
X value is not significant
Loop Open phone on-hook
Loop Closed phone off-hook