Nortel T1/SMDI Configuration Manual page 163

February 2008
Note: If the Channel Bank is master timed, the CallPilot server must be
slave timed.
CallPilot T1 signalling requirements
T1 uses in-band signaling to indicate the status of each T1 channel. Control
signals are transmitted in the same channel as the message (that is, voice
data).
Signaling indicates the state of both terminals: the switch line card and
the CallPilot agent. (for example, on-hook)
T1 uses robbed bit signaling. This means that specific bits in the data
stream are replaced with control information.
The signaling mechanism is specified as part of the frame format.
CallPilot supports only SuperFrame (SF) format framing. In SF, the
eighth (least significant) bit of each time slot in the sixth and twelfth
frames are robbed to provide per channel signaling. The bit from the
sixth frame is called the A bit. The bit from the twelfth frame is called
the B bit.
This provides, at most, four signaling states for each terminal.
The following table displays the meaning of the different signaling states
that CallPilot uses to indicate the status of an agent to the switch.
T1/SMDI and CallPilot Server Configuration
CallPilot T1/SMDI interfaces
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