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DTMF Problem in Cisco MCU 5320



One of our customers has Cisco Contact Center enterprise solution. They have also video enabled agents. They want to record the video calls between their customers and the agents. To do that we installed a Cisco TCS and a Cisco MCU 5320. And we created a meeting room on the MCU. The meeting room has two predefined participants: IVR number reaching the agents and the recording alias on the TCS. So when a customer dials into the meeting room a conference starts between the customer, the TCS and the Contact Center IVR. After that the customer need to send some dtmf codes to the IVR through the MCU so that they can connect to the agent. But the MCU doesn't forward the DTMF codes to the Contact Center IVR. I think there is a problem on dtmf protocols between the MCU and the Contact Center (or CUCM). Do you think we can solve this problem?

Any help would be really appreciated,

Best regards,


5 Replies 5

Patrick Pettit
Cisco Employee
Cisco Employee

Hi Tufan - What type of tones does the IVR need to receive?  Inband or out of band DTMF?

I believe, MCU will only send out, in band DTMF tones through the conference.  Will have to confirm this to be sure.

In your conference configuration navigate to participant controls.  Where you see "Mute In Band DTMF", try setting the setting to Never. 

From the online help:

Never: the in-band DTMF  will never be muted. Any DTMF tones sent from these endpoints will be audible to conference participants.

This is a per-conference option, but you can still enable or disable the muting of in-band DTMF  on a per-participant basis.

In some circumstances, you might need to override this setting  for individual endpoints. For example, where a conference is cascaded  onto an audio bridge, it might be useful for one of the participants in  that conference to be able to send in-band DTMF to the MCU. This is for  the purposes of sending the conference ID or PIN to the audio  conferencing bridge. In this case, the Mute in-band DTMF  setting for the endpoint of that participant needs to be Never (and you configure this in an endpoint's configuration, see Configuring an H.323 endpoint and Configuring a SIP endpoint).

For  ad hoc conferences, you can configure the Mute in-band DTMF  setting through the ad hoc conferences template. You can also edit the Mute in-band DTMF setting for individual active ad hoc conferences.

Hope this helps..and your IVR for contact center take in band DTMF versus out of band only as this seems the only way for it to work. 

Let me know if this helps. 



Actually I don't know which type of DTMF tones are supported by the IVR. The customer is using Cisco Contact Center Enterprise. Who do I need to ask the question? Should I have needed to open the discussion in voice side?


Patrick Pettit
Cisco Employee
Cisco Employee

Hi Tufan. No, this is the right place. Have you tried what I suggested?

Sent from Cisco Technical Support Android App

Yes, I tried all what you suggested. But it is still same.



I would also do it like Patrick said.

What I would use are the following settings on the MCU for this kind of conference:

Could you tell us a bit more about the involved components, version numbers, call flow/path incl call protocols and codecs used.

DTMF can be tricky from time to time as there are different ways in- and multiple out of band.

I would look into that. You could also try for example to use h323 to the MCU instead of SIP (or vice versa)

and also check on the neigbor zones just to see if it makes a difference.

I assume you use a VCS for video b2b calls and the mcu registration and sip trunk to cucm/contact center?

In addition what do you think about reaching out to you to check with your Cisco contact to file a feature request to

have a more scaleble recoding feature within the infrastructure.

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