Greetings!
I was wondering if there is any way to use higher sample rate frequencies for DTMF, as this seem to be a requirement?
We got reports from some partners that DTMF failed when connecting with OPUS. After some investigating of the SIP-messages we saw that the incoming INVITE contained telephone-event lines both for 8000 and 48000, but in the response from Asterisk (18.13.0) only a line with 8000 is present in the SDP. This seem to break the DTMF handling for the calling party.
After googleing a bit, I found some posts refering to problems of this kind, like:
https://groups.google.com/g/discuss-webrtc/c/LntxAkr2H_U
which refers to:
saying that here it is stated that one must use the same frequency.
I also found an old post from the asterisk-dev mailing list that asks about the same issue:
https://asterisk-dev.digium.narkive.com/eEcODzly/telephone-event-at-rates-other-than-8000
The response from Joshua Colp indicates that there is no support for this, but it is a quite old posting so things may have changed.
So what is the current status? Is there a way to handle this currently? If not, should this be regarded as a bug? (If the above postings are correct when claiming it is mandatory).
Best regards,
Torbjörn Abrahamsson