Core Issue
This symptom may be observed when hairpinned calls are placed with a Cisco 3725/3745/2691 gateway with AIM-ATM-VOICE-30 module installed and running Cisco IOS version 12.2(15)ZJ03 or 12.3(07)T.
You can verify that the symptom occurs through the output of the show connection all EXEC command.
The command output shows one timeslot twice and shows that it is connected to both another timeslot and to a Digital Signal Processor (DSP) DSP resource.
The command output indicated shows a timeslot 1 connected to timeslot 23 (22) as well as DSP 07/00/00. There should be a single timeslot-to-timeslot or DSP connection, but not to both at the same time, as shown:
2691# show connection all
ID Name Segment 1 Segment 2 State
========================================================================
2 V-022-701 T1 0/2(VOICE) 01 DSP 07/00/01 UP
3 V-023-702 T1 0/2(VOICE) 02 DSP 07/00/02 UP
4 V-024-703 T1 0/2(VOICE) 03 DSP 07/00/03 UP
5 V-025-710 T1 0/2(VOICE) 04 DSP 07/01/00 UP
6 V-026-711 T1 0/2(VOICE) 05 DSP 07/01/01 UP
7 V-027-712 T1 0/2(VOICE) 06 DSP 07/01/02 UP
8 V-028-713 T1 0/2(VOICE) 07 DSP 07/01/03 UP
9 V-029-720 T1 0/2(VOICE) 08 DSP 07/02/00 UP
10 V-0210-721 T1 0/2(VOICE) 09 DSP 07/02/01 UP
11 V-0211-722 T1 0/2(VOICE) 10 DSP 07/02/02 UP
12 V-0212-723 T1 0/2(VOICE) 11 DSP 07/02/03 UP
13 V-0213-730 T1 0/2(VOICE) 12 DSP 07/03/00 UP
14 V-0214-731 T1 0/2(VOICE) 13 DSP 07/03/01 UP
15 V-0215-732 T1 0/2(VOICE) 14 DSP 07/03/02 UP
16 V-0216-733 T1 0/2(VOICE) 15 DSP 07/03/03 UP
17 V-0217-740 T1 0/2(VOICE) 16 DSP 07/04/00 UP
18 V-0218-741 T1 0/2(VOICE) 17 DSP 07/04/01 UP
19 V-0219-742 T1 0/2(VOICE) 18 DSP 07/04/02 UP
20 V-0220-743 T1 0/2(VOICE) 19 DSP 07/04/03 UP
21 V-0221-750 T1 0/2(VOICE) 20 DSP 07/05/00 UP
22 V-0222-751 T1 0/2(VOICE) 21 DSP 07/05/01 UP
24 V-021-0223 T1 0/2 00 T1 0/2 22 UP
25 V-0223-752 T1 0/2(VOICE) 22 DSP 07/05/02 UP
26 V-021-700 T1 0/2(VOICE) 00 DSP 07/00/00 UP
Resolution
Reboot the voice gateway to fix the no-way audio problem. To prevent the problem from occurring, configure the gateway so hairpinned calls do not occur.
A workaround for this problem is available in version 12.3(07.11)T1, which can be downloaded from the Software Center.
For details, refer to Cisco bug ID CSCed79214.
