09-12-2013 02:52 PM - edited 03-16-2019 07:21 PM
We have a server running voice dictation application and connected to 48 analog phone lines from a pair of VG224's. We did VTSP debug on these VG's and found that there are random duplicate digits dialed from the VG to the server, which has caused a lot of issue for user authentication. E.g. user name 12345 may become 123345. The VG is running MGCP with our CallManager. Is this an issue with DTMF? IOS version 12.4(22)T5. I didn't see DTMF related bugs with this release. Thanks.
09-12-2013 07:09 PM
Probably is an issue with the DSPware... You can try upgrading IOS to 15.1(4)M6.
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Jorge Armijo
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09-12-2013 07:36 PM
After reviewing the traces from the CallManager, we found that the duplicate digits are also seen on the CallManager. Does this indicate a human error? Or could it be something wrong with the CallManager or the Cisco phone??
Thank you for the input Jorge. I'd like to understand exactly what happened before looking into upgrading the IOS, unless it's confirmed that we hit a bug in this release.
09-16-2013 05:52 PM
If you want to understand the reason for the failure, you'll need a PCM capture, with mgcp debugs on the VG, CCM traces and a sniffer trace. All that information will show us if the VG is sending both in-band and out-of-band tones, which will explain the double digits.
Of course it's easier to upgrade IOS/DSPware and monitor the outcome
HTH
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Jorge Armijo
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09-17-2013 06:51 AM
Hi Jorge
Thanks a lot for the information. After further troubleshooting, we found the issue in the upstream voice gateway router, not the VG224. The upstream router was missing the DTMF relay out-of-band command, which resulted in leaking DTMF in-band. The missing command was added last night, and everything looks great so far.
The issue was misleading initially because the testing user insisted she didn't make mistakes when making those testing calls. Until later we found a different issue, that the VG224 has sent the correct digits but the listening server received much more digits than it should. This led us to realize that there was no issue between the CallManager and VG224, but further up between our Nortel PBX and the CallManager.
09-19-2013 01:59 PM
I just wanted to add that we encountered this exact same issue. It was discovered when we connected an old analog polycom to a VG224 and users were dialing into conference bridges, and the PIN would come back incorrect. We did a debug vpm signal and did not see the extra digits being send.
We did not have this issue with any IP Phones or IP Polycoms and I was able to re-create it with a standard analog phone, so we were pretty sure the issue was the VG224..
In our case, we entered the following command into the VG224 ONLY (we did not need to add it to the upstream 2911 where the outbound PRI terminates):
mgcp dtmf-relay voip codec all mode out-of-band
(then did a "no mgcp" , "mgcp" for it to take affect)
The IOS version of the VG224 is: slot0:vg224-i6s-mz.124-24.T5.bin
09-20-2013 08:53 PM
Really nice you found the issue!
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Jorge Armijo
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