Further testing showed the delay can be eliminated by removing the number in the legacy AT&T system and re-configuring it as we do for Cisco phone numbers. I then created the same number in CUCM that routes to a Call Handler. We have 2 systems, migrating to all Cisco at some point. Previously, the number was on a port in the AT&T system call forwarded to Cisco Unity. Strange though, that calling such a number, the delay occurred whether the Caller Input destination was a Cisco or AT&T phone. So, in the case of the Caller Input destination being a Cisco phone, the delay would still occur. In this case the call is completely out of the AT&T system. There was never a delay when calling a number initially, it would route immediately to the greeting associated Call Handler.

The delay will still occur though in a few instances where the initial called number resides in the AT&T system and is no answer call forwarded to a Call Handler in CUCM.