[asterisk-users] Asterisk 18 won't transcode DTMF to inband

[Kingsley Tart]

I forgot to mention that pjsip.conf for this endpoint (that doesn't
support telephone-event) already has this:

dtmf_mode=auto

Cheers,
Kingsley.

On Tue, 2021-10-19 at 15:19 +0100, Kingsley Tart wrote:
> Hi,
> 
> I'm using Asterisk 18 to receive a call via SIP, dial a different SIP
> destination and bridge them together.
> 
> However, even if the destination indicates that it doesn't support
> telephone-event, Asterisk is still sending DTMF as events, not
> transcoding to inband.
> 
> Asterisk is recognising inband DTMF coming in to it, but if it
> receives
> DTMF in RTP events it just forwards them on instead of transcoding.
> 
> eg, the SDP in the INVITE that Asterisk sent out:
> 
> v=0.
> o=- 1051458170 1051458170 IN IP4 88.151.41.28.
> s=Asterisk.
> c=IN IP4 88.151.41.28.
> t=0 0.
> m=audio 13470 RTP/AVP 8 0 3 9 110 117 119 101.
> a=rtpmap:8 PCMA/8000.
> a=rtpmap:0 PCMU/8000.
> a=rtpmap:3 GSM/8000.
> a=rtpmap:9 G722/8000.
> a=rtpmap:110 speex/8000.
> a=rtpmap:117 speex/16000.
> a=rtpmap:119 speex/32000.
> a=rtpmap:101 telephone-event/8000.
> a=fmtp:101 0-16.
> a=ptime:20.
> a=maxptime:60.
> a=sendrecv.
> 
> 
> The SDP in the response, notably without telephone-event:
> 
> v=0.
> s=sip call.
> c=IN IP4 109.159.136.164.
> t=0 0.
> m=audio 63356 RTP/AVP 8 0 3 9.
> a=rtpmap:8 PCMA/8000.
> a=rtpmap:0 PCMU/8000.
> a=rtpmap:3 GSM/8000.
> a=rtpmap:9 G722/8000.
> a=ptime:20.
> a=sendrecv.
> 
> Any idea how I can fix this?
> 
> Cheers,
> Kingsley.
> 
>