Try adding the following two commands to the PRI interface:
interface pri 1
isdn name-delivery setup
calling-party name-facility-timeout 1
This kind of delay on a PRI connection is often due to the Adtran device waiting on CNAM from the PBX that is never sent. The above should greatly reduce or eliminate it.
My device doesn't have the calling-party name-facility-timeout command in it. Here is the Adtran version I am running.
ADTRAN, Inc. OS version R11.10.1.E
Mainline Version: ENM.15.156
P4 Changelist: 234321
Built on: Tue Jan 26 17:46:49 CST 2016
Hardware version R.188.8.131.52-0
Boot ROM version R10.9.3.B2
Built on: Mon Jul 6 16:47:40 CDT 2015
Compatibility Version: 1
Copyright (c) 1999-2016, ADTRAN, Inc.
Platform: Total Access 908e (3rd Gen), part number
Flash: 97120256 bytes DRAM: 509648896 bytes
TA908e uptime is 0 days, 0 hours, 4 minutes, 6 seconds
slot 0, DSP 1
DSP software version: G3.R1.3..0-R
DSP hardware version: Freescale BSC9131
Total channels: 60
System returned to ROM by Soft Reset
Current system image file is "T900E3A-R11-10-1-E.biz"
Boot system image file is "T900E3A-R11-10-1-E.biz"
Primary system configuration file is "startup-config"
After having issues with getting a license error after upgrading the firmware so I called support. They found that the Adtran was trying to send calls from one SIP trunk to another SIP trunk and that was causing the delay. to do this we had to add a permit and deny to each trunk group.
Thanks for your help.