Non-Isup Trunks - Nortel DMS-250 Reference Manual

Non-ISUP trunks

The call scenario in Figure 6-5 illustrates interworking with a non-ISUP
trunk within the network. Note that the ACM is mapped to a progress
(instead of an alerting) message, indicating that interworking has been
encountered. At the per-trunk signaling (PTS)/PRI interface, all Q.931
messages are received but ignored. Progress description in the progress
indicator (PI) is set to "not end-to-end ISDN."
Figure 6-5
Interworking with a non-ISUP trunk within the network
(PRI)
PBX
SETUP
CALL PROC
PROG
CONN
CONN ACK
DISC
REL
REL COM
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
(ISUP)
DMS-250 DMS-250
IAM
ACM
Ringing
ANM
Active call
REL
RLC
PRI interworking 6-7
(PTS) (PRI)
DMS-250
Seizure
Digits
SETUP
CALL PROC
PROG/ALERT
Answer CONN
CONN ACK
On-hook DISC
On-hook REL
REL COM
PBX