rfc2833 support for dtmf in sip.js 0.17.x

[anshk...@gmail.com]

I didn't find any option to enable support of rfc2833 in-band dtmf support in latest sip.js version 0.17.x

While it was available in earlier version like it was till 0.15.x but I didn't find option to configure same. Does anyone have idea about how to or is there any reason to remove it?

[Slavik Bialik]

As far as I know it only supports SIP INFO. And then you'll have to use a gateway (like FreeSWITCH) to convert it to RFC2833 and then it goes to PSTN. (This is what I am doing)

Looked briefly in 0.15.x documentation and I couldn't find any reference to RFC2833 in the docs. 

Anyway, it makes sense as SIP.js is not doing anything that relates to audio. Only signaling. So don't think they can inject DTMF as in-band.

[James Criscuolo]

DTMF via RTP or INFO are both still possible, please follow our migration guide: https://github.com/onsip/SIP.js/blob/master/docs/migration-0.15-0.16.md

[Slavik Bialik]

Looks like the migration guide is only suitable for 0.15 -> 0.16.

But in the migration guide of 0.16 -> 0.17 there's no mention at all to "dtmfType" and RFC2833, so I guess they removed this ability - not sure. Anyway, in 0.17 seems like there's no "dtmfType" under the user agent settings.

[Eric Green]

DTMF in SIP is built on top of other ideas. It is not really a SIP standard thing, so we decided to give consumers of SIP.js the ability to build DTMF to meet the needs of their application.

If you need to send RTP DTMF, and you environment supports it, the default web session description handler has a function sendDtmf https://github.com/onsip/SIP.js/blob/master/docs/session-description-handler/sip.js.sessiondescriptionhandler.senddtmf.md you can call

[Slavik Bialik]

Nice. Thanks Eric!

[anshk...@gmail.com]

Eric, I followed exact way you've described in document to send in-band dtmf but it's always returning with false for me.