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troubleshoot DTMF issue with FXS port

Can anybody help with a troublshooting exercise any tips would be great.

I have a vg224 gateway registered with UCM 6.1 using SCCP. Analogue conference phones dial out to a provider via a H323 Gateway with an E1. Intermittent when the users get connected to the remote conference service and enter digits the digits are not recognized by the conference provider. I have check all the network and looks clean, no wan links involved, just a small lAN segment all running 100 meg full duplex. is there any way to debug the tones going out the gateway. I have also checked the clocking and controller all look good, the client has no issues with voice and the sccp messages all work fine back to UCM.

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Accepted Solutions
Cisco Employee

Re: troubleshoot DTMF issue with FXS port

Hi,

Which IOS and DSP ware version do you have? I've heard of issues with DSP Ware, where you need to downgrade it

to fix DTMF issues. Sounds like a bug too, please check this one:

CSCso87127 in-band DTMF leakage of 40-50msec observed when using DTMF relay

Symptom:

DTMF digits generated after a call connects may experience intermittent double digits which in turn may cause issues when interworking with certain systems like IVR which utilize DTMF for signaling.

Conditions:

Double DTMF digits may be experienced in an environment with Cisco IOS VoIP gateways.

The issue is that the VoIP gateway with the voice-port detecting the DTMF in conjunction with out-of-band (OOB) DMTF relay may allow a small portion of the DTMF to be sent in-band in the RTP stream.

This could then cause the terminating device/gateway to generate the DTMF from the OOB DTMF relay method as well as allowing the in-band DTMF present in the RTP stream through resulting in the possibility of double DTMF digits being detected.

This would be present only after a call has connected where DTMF digits may be relayed in an RTP stream.

This issue is present on 5510 DSPs on Cisco IOS VoIP gateways running with a release of dspware of 4.4.27 and 9.4.5 and later. The dspware comes bundled with the IOS release. In gateways that support 5510 DSPs, this release can be manually changed independent of the IOS release. To verify the release running on a gateway, confirm the firmware version with the command show voice dsp group all

Workaround:

Disable DTMF relay would prevent this problem from occurring. This may cause other problems and would not generally be the recommended action with using codecs other than G711/G722.

Downgrade IOS to a release that contains a prior dspware release or work with the TAC to get access and guidance on a possible dspware to load while retaining the IOS release currently in use.

This bug is fixed in DSPware 9.4.7, which is packaged in with IOS 12.4(15)T8.

Hope this helps!

Regards,

Teresa.

If this helps, pleas rate! :)

Regards, Tere. If you find this post helpful, please rate! :)
3 REPLIES
Cisco Employee

Re: troubleshoot DTMF issue with FXS port

Hi,

Which IOS and DSP ware version do you have? I've heard of issues with DSP Ware, where you need to downgrade it

to fix DTMF issues. Sounds like a bug too, please check this one:

CSCso87127 in-band DTMF leakage of 40-50msec observed when using DTMF relay

Symptom:

DTMF digits generated after a call connects may experience intermittent double digits which in turn may cause issues when interworking with certain systems like IVR which utilize DTMF for signaling.

Conditions:

Double DTMF digits may be experienced in an environment with Cisco IOS VoIP gateways.

The issue is that the VoIP gateway with the voice-port detecting the DTMF in conjunction with out-of-band (OOB) DMTF relay may allow a small portion of the DTMF to be sent in-band in the RTP stream.

This could then cause the terminating device/gateway to generate the DTMF from the OOB DTMF relay method as well as allowing the in-band DTMF present in the RTP stream through resulting in the possibility of double DTMF digits being detected.

This would be present only after a call has connected where DTMF digits may be relayed in an RTP stream.

This issue is present on 5510 DSPs on Cisco IOS VoIP gateways running with a release of dspware of 4.4.27 and 9.4.5 and later. The dspware comes bundled with the IOS release. In gateways that support 5510 DSPs, this release can be manually changed independent of the IOS release. To verify the release running on a gateway, confirm the firmware version with the command show voice dsp group all

Workaround:

Disable DTMF relay would prevent this problem from occurring. This may cause other problems and would not generally be the recommended action with using codecs other than G711/G722.

Downgrade IOS to a release that contains a prior dspware release or work with the TAC to get access and guidance on a possible dspware to load while retaining the IOS release currently in use.

This bug is fixed in DSPware 9.4.7, which is packaged in with IOS 12.4(15)T8.

Hope this helps!

Regards,

Teresa.

If this helps, pleas rate! :)

Regards, Tere. If you find this post helpful, please rate! :)
New Member

Re: troubleshoot DTMF issue with FXS port

thanks for the info i will check tomorrow when logged in.

New Member

Re: troubleshoot DTMF issue with FXS port

this fixed my issue, thanks for the post

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