DTMF Tones Not Working for IVR Calls

[Azza]

Currently utilising Cisco 8845 phone handsets with Cisco WebEx Calling, All cloud-managed via WebEx.

The issue we currently are having with the desk phones is calling numbers that have Interactive Voice Response and the DTMF Tones not being recognised when a number option is selected. None of the numbers or hash/asterisks are recognised in the calls.

I have gone through extensively over the device options, and options within cisco webex calling on the admin portal and can't find an option that rectifies this. With our VOIP Provider, it's all set to Ïn-Band DTMF Tones as set and required for most Australian Based Telecommunications Companies. The only thing I could find on a search on google is that the call quality and codec used could cause issues with the tones being recognised by the receiving end but honestly, the call quality is great so I don't think that is an issue. Obviously, the workaround at the moment is to utilise our mobile telephones for these service numbers but it's extremely annoying not being able to use our desk phones for these calls. If anyone has come across this sort of issue before I would be very appreciative of any feedback or assistance on this.

[Justinwong19918]

I have same issue on 8845 and 8865  phone 

however, the dtmf-relay rtp-nte already applied all the dial-peer , still not working. 

only working on 7841 phone . 

any idea?

[Azza]

Try Factory Resetting your 8800 series phones and let them download their configuration fresh again. Other than that log a ticket with cisco.

[dtibbe]

Ah,

* does this occur only for outgoing calls to other provider's IVRs?

* does this occur also for incoming calls to a WxC AA?

* WxC to WxC AA works properly, I guess?

* Do you have another org with WxC at the same provider, do there WxC to WxC AA calls work? In such a scenario, the call should go through PSTN as well,  but not leave the provider's network

[Azza]

Yes, it's only for outgoing calls to other providers' IVR's.

[dtibbe]

Sorry, what's WebEx? Are you referring to Webex?

With Webex Calling, we had similar issues in the very beginning and only from some external providers. Finally, our CCP provider checked into that and the cause was exactly what you've already mentioned: Some carriers use different codecs than others and the provider does not transcode. Check with your CCPSTN-Provider or the LGW requirements for DTMF codecs and inband/rtp event and ensure that the settings/expectations fit..

[Azza]

Yes, I was referring to wEbEx. Sorry, my Grammarly plug-in thinks Webex is WebEx for some reason.

A quick look at my SIP Providers requirement:

"The Voice Codec is G.711, aLaw 20Msec, with inband DTMF Prefered."

A quick look at the running-config of the Cisco ISR 4321:

voice class codec 99
codec preference 1 g711ulaw
codec preference 2 g711alaw

I will remove the ulaw codec from the preference list and make the alaw preference one.

I will get back to you if this resolves the issue.

A packet capture of the RTP packets and logs from the phone show that the DTMF tones made it to the ISR and the Cisco TAC technician mentions that this does not make it to the back end service at all on their end, so we may have our smoking gun.

Thanks for your reply!

[Joe_Tseng1]

Is this issue resolved ?

[Azza]

Yes, this was resolved but not due to a codec issue, there was an entry missing in the config on the CISCO IVR to allow outgoing DTMF tones for the Cisco broad-cloud SIP peer. It took almost a year to get Cisco to escalate this through their normal support channels until I got a technician that was not a turnip to identify what the exact issue was. It was apparently staring us all in the face. This line was missing from the startup-configuration "dtmf-relay rtp-nte" under "dial-peer voice 201 voip".