In-band DTMF on SIP-trunk?

Unanswered Question
May 28th, 2010

We're using a new SP that uses in-band dtmf for incoming calls. DTMF in outgoing calls works fine out-of-the-box but incoming to the AA doesn't.

Does the UC500 handle in-band and if so how do one configure it?

Best regards


I have this problem too.
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Alberto Montilla Mon, 05/31/2010 - 09:01

Dear Sir;

Yes. Inband DTMF to the autoattendant is supported. Which SP are you using.


m.junghage Tue, 06/01/2010 - 02:07

Hi Alberto,

Thank you for your reply.

The SP in this case is TeliaSonera, Swedens largest SP. In the specifications it list support for the following standards, does the UC-series support these?

• RFC 3261, “SIP: Session Initiation Protocol”
• RFC 3263, “Session Initiation Protocol (SIP): Locating SIP Servers”
• RFC 3265, “Session Initiation Protocol (SIP)-Specific Event Notification”
• RFC 3323, “A Privacy Mechanism for the Session Initiation Protocol (SIP)”
• RFC 3428, “Session Initiation Protocol (SIP) Extension for Instant Messaging”
• RFC 3489, “STUN – Simple Traversal of User Datagram Protocol (UDP)
Through Network Address Translators (NATs)”
• RFC 3581, “An Extension to the Session Initiation Protocol (SIP) for Symmetric
Response Routing”
• RFC 2916, “E.164 number and DNS”
• RFC 2778, “A Model for Presence and Instant Messaging”
• RFC 2779, “Instant Messaging / Presence Protocol Requirements”
• draft-ietf-sip-publish-03, “An Event State Publication Extension for the Session
Initiation Protocol (SIP)”
• draft-ietf-impp-cpim-pidf-08, “Presence Information Data Format (PIDF)”
• draft-ietf-simple-presence-10, “A Presence Event Package for the Session
Initiation Protocol (SIP)”
• draft-ietf-simple-winfo-package-05, “A Watcher Information Event Template-
Package for the Session Initiation Protocol (SIP)”
• draft-ietf-simple-winfo-format-04, “An Extensible Markup Language (XML)
Based Format for Watcher Information”
• draft-ietf-sip-connect-reuse-01, “Connection Reuse in the Session Initiation
Protocol (SIP)”

• draft-ietf-sipping-sos-00, “Emergency Services URI for the Session Initiation
• draft-ietf-iptel-cpl-09, “CPL: A Language for User Control of Internet Telephony

Alberto Montilla Tue, 06/01/2010 - 02:28

Dear Sir;

UC 500 supports majority of those, although I cannot express direct compliance for each of those individually. If you can provide me with the specifications of the SIP trunk (whether it requires registration), what type of codec, what type of DTMF method, I should be able to generate a template for CCA which you should be able to use to configure SIP trunking for this customer.

Information required is available at (please provide the info):

How to import the template (I would generate it for you)


m.junghage Fri, 06/11/2010 - 02:25

Hi Alberto,

I'm trying to get some information in english from the provider. They don't offer a lot of documentation even in swedish so it may be a long shot. I'll post it as soon as I get it.

Best regards


m.junghage Fri, 06/11/2010 - 06:14

This is the reply I got from the SIP SP: /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normal tabell"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

"DTMF is not handled in any special way. DTMF tones are transmitted in the RTP stream of voice packets coded by G.711 codec."

How would this be configured in the UC520?

Best Regards


David Trad Wed, 03/23/2011 - 18:13

Hi m.junghage,

It would seem that your ITSP supports only G.711 Codec, this means you will need to change your voice-class Codec priority to have G.711 as number 1 and or the only one. Otherwise you could ask them to support G.729 as well.

If they only support one type of Codec then you need to make sure your Dial-Peer has this as well, this way all the information such as DTMF are all going to work as they should.




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