As mentioned in a previous conversation, we've got a Cisco 2821 ISR running CME 4.0(2) which is connected to an Alcatel 4200 legacy PBX. The ISR is a gateway to the PSTN so the Legacy PBX sits behind it, connected via an E1 link (Primary Rate Interface).
In order for the Legacy PBX to reach the PSTN, it adds a prefix ("5432") to each call placed. The ISR then uses this prefix to match an outgoing dial-peer. This configuration has been tested and works fine.
The only snag is that there's a HUGE delay between the last digit being received from the Legacy PBX and the ISR actually placing the call.
On the Serial interface to the legacy PBX we need to run "isdn overlap-received" because the Legacy PBX sends the digits one by one. I've got the "interdigit timeout" on all concerned voice-ports set to 3 seconds. I've also tried playing around with several ISDN timers but no results.
I've tried changing the timeout values but I still get roughly a 15 second delay between the last digit being received and the actual call being placed.