User Manual
SUPM1
page 38 of 94© KEYMILE December 2015 EN/LZTBU 372 129/1 RC
94
Functional Description
Table 30: MCAS PBX extension signalling
CAS bit State
a b c d downstream upstream
0 0 0 1 Disconnect clear Ground key
0 1 0 1 Call established Off-hook
0 1 1 1 Metering pulse -
1 0 0 1 Ringing off -
1 0 1 1 Ringing on -
1 1 0 1 Circuit free (idle) or busy On-hook
1 1 1 1 Blocking (AIS) Blocking (AIS)