ISDN PRI - No outbound ringback on SOME calls

[aperron]

Hi All-

Bit of an odd situation with a customer that's stumping me.  System is an MXe-III running 8.0 SP3 PR2.

They're saying that when calling some but not all external numbers, they hear silence instead of ringback tone.  The carrier investigated and determined this was indeed occuring, but said that their switch couldn't be configured to solve the issue as it is obsolete and being replaced at some point in the future.  Total crap in my opinion, but nonetheless they won't budge.  They are saying we need to make our PBX provide the users ringback on all outbound calls.

The circuit is a pretty vanilla NI-2 PRI, central office switch is a DMS-100.  I'm at a loss with here to begin trying to configure our switch to handle this task.

Does anyone have any pointers or tricks to make this work?

[JasonTaylor]

Customer has just reported this on a DASS circuit after changing ARS away from an ISDN30 which is due to be ceased.  The DASS should be obsolete but many sites are still running them.  Did you get to the bottom of the problem?