In-band dtmf support for Cisco Phones

[gpsriramdc]

Hi All,

Cisco Phones supports Inband dtmf ??

Setup

Phone --> CUCM --> CUBE ---> Service Provider

1)We are doing the SIP Integration with service provider (codec G711), where some calls are negotiated with rtp-nte and some calls are negotiated with inband.

2)Calls negotiated with inband dtmf is  not working. Hope DSP resource requires for rtp-nte to Inband conversion.

3)When i tried to keep the default configuration in CUBE incoming dial peer (no dtmf -realy), CUCM couldn't negotiate for any method and declared as no dtmf  for the call.

"SIP DTMF Info: mLocalDtmfCaps...UNSOL=1, KPML=1, Inband=1(0) mEndppointsDtmfCaps...UNSOL=0, KPML=0, Inband=0(0) mDefaultTelephonyEvent=101, mDtmfPreference=1, mMtpAllocated=0

DET-MediaManager-(249255)::isMTPNeededForDTMF, No DTMF is possible for call since one (or both) party does not support any DTMF cap party1DTMF(3) party2DTMF(0)"

Thanks in Advance....

[Manish Gogna]

Hi,

Cisco phones do support inband dtmf (  RFC 2833 (RTP-NTE) ). You can verify your config as per the following links which talk about different dtmf options available and how to configure them

https://supportforums.cisco.com/blog/154706

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book/dtmf-relay.html

Manish

[gpsriramdc]

Hi Manish,

Thanks for your reply.

I mean the "G711 audio" as "inband" as mentioned in the CUBE dtmf relay configuration link [http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book/dtmf-relay.html]  which is difference from RTP-NTE..

Thanks in Advance....

[Manish Gogna]

Hi,

As per the following

http://www.cisco.com/c/en/us/support/docs/unified-communications/unified-border-element/200412-DTMF-Relay-and-Interworking-on-CUBE.html#anc6

Support for In-band audio DTMF through G711

Voice In-band audio or G711 DTMF refers to the transport of audible tones over the voice audio stream, without any additional involvement of the signaling protocol or the DSP for their transmission other than to setup the call normally and pass the audio end to end using the G711Ulaw/Alaw codec. This means that the CUBE/IOS only passes the audio of the tones coming from one end to the other as if it is normal voice audio. The important measure to take for this method is to ensure that the calls are getting established using the G711Ulaw/Alaw codec specifically because using a codec that would compress the audio (any other codec than G711) distorts the DTMF tones and is likely render them unrecognizable to the receiving end. This is because the compression algorithm utilized by high compression codecs was designed to recognize and predict human voice and not DTMF tones.

In-band audio/G711 DTMF is supported with any VoIP signaling protocol and only requires the G711 codec to be enforced for the calls end-to-end. One must also must keep in mind that the any transcoding treatment from a low-bit-rate (LBR) codec to G711 most likely distorts the tones as well.

DTMF interworking between Inband G711 to RFC2833

CUBE is able to interwork between Inband G711 DTMF (raw audio tones) to RFC2833. However, these requirements need to be met

• The codec used must be G711 end-to-end. This is a restriction because if a LBR codec was to be used then the tones would get distorted due to the compression loss.
• Transcoding resources must be available and registered with the CUBE accordingly. This because the CUBE needs to allocate a transcoding resource (more specifically: a DSP resource) to the media RTP stream to inject or listen for tones within the audio stream.
• The dial-peer for the inband-tones leg must not have any DTMF relay command configured.
• The dial-peer for the RFC2833 leg must have dtmf-relay rtp-nte configured.
• Do not enable digit-drop on any of the dial-peers involved with the call.

Manish

[MOHIT SINGH]

Hello,

As per below doc, it is recommended to use CUBE to convert raw inband DTMF into RFC2833.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab10/collab10/trunks.html

You will have to register a transcoder on the CUBE (not with CUCM) to do the DTMF conversion. The inbound and out bound dial peer should be configured accordingly. One with "no dtmf-relay" and other with "dtmf-relay rtp-nte"

[gpsriramdc]

Hi All,

Thanks for all your comments.

am looking for official document where it mentions "Cisco IP Phones not supporting Inband tones"..

Please help on this.

[HARIS_HUSSAIN]

Did You find any document specifying the same

[damir.omanovic]

Hi gpsriramdc, I have the same issue. Did you solve?

[wangbin006599]

hello,friend.this problem is solved?

i also face the problem.i hope i can get some information about the problem!!!!!

thank you!