Cas To Btup And Btup To Cas Signaling - Nortel DMS 100 Series Maintenance Manual

4-4 RSC-M Signaling and Communications
•
•
BTUP timers:
•
•
•
•

CAS to BTUP and BTUP to CAS signaling

This section illustrates the signaling sequences used during normal CAS to
BTUP, and BTUP to CAS calls. The BTUP trunk indicated is not connected
between the originating and terminating offices. Releases that are not normal,
caused by the time-out of timers:
•
•
•
The following figures, refer to the CAS signals by name. Refer to table "CAS
incoming signals" for the CAS incoming signal codes. Refer to table "CAS
outgoing signals" for the CAS outgoing codes. Descriptions of the call
processing events follow each figure.
297-8223-550 Standard 04.02 November 2000
T3-restarts after each digit is received. Time-out indicates all digits are
collected and starts T7.
Timed-release disconnect (TRD)-long release disconnect timer. Starts
when the terminating line suspends (SUS) the call. Stops if the terminating
line restores (RES) connection before time-out. If TRD times out, the call
is dropped.
T1'-starts when release (REL) is sent. Stops when release clear (RLC) is
received.
T5-release supervision timer. Refer to T1'.
T7-starts when T3 stops. Indicates digits collected and IAM message is
sent. T7 stops when terminating exchange sends ACM message back.
T9-starts when T7 stops. Call established setup speech conditions.
T1 which is the total call setup time
T7 which is the time between IAM and ACM
TRD which is the time between terminator delay and requests to establish
again