MAUUI 19-5
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
Figure 19-2
PRI–PRI Call Clearing before Alerting when Treatment Applied
Q.931 Call Proceeding
Q.931 Call Proceeding
Q.931 Setup (UUI)Q.931 Setup (UUI)
Q.931 DISConnect (UUI)
Q.931 DISConnect
Q.931 RELease
Q.931 RELease
Q.931 RELease COMPlete
Q.931 RELease COMPlete
Q.931 Progress (UUI)
Applied tones or announcements
MWC DMS-250
PRI–PRI Call Clearing After Alerting/Before Connect
There are two scenarios concerning User-to-User Interface (UUI) delivery in
a call clearing message before the terminator sends an indication of answer.
In the first scenario, the originating PRI agent includes UUI in the Q.931
Setup message to invoke the MAUUI service. The Q.931 Setup message
with UUI is sent to the terminating PRI agent. The terminating PRI agent
responds to this message with a Q.931 Alerting message and this message is
transported to the originating agent (UUI is included if received in the Q.931
Alerting message). The terminating agent then sends a Q.931 DISConnect
message with UUI. If treatment is not to be applied at this switch, the UUI is
transported to the originating PRI agent in the corresponding Q.931
DISConnect message. The following diagram shows the PRI to PRI call
clearing before connect when treatment is not applied.