[asterisk-users] chan_pjsip: DTMF mode "auto_info" on endpoints

[Floimair Florian]

Hey all!

I recently tried the dtmf_mode "auto_info" on my setup to support endpoints that only understand SIP INFO as a fallback.

My setup is the following:

Endpoint A (RFC4733) --> Asterisk <-- Endpoint B (SIP INFO)

Both are configured with "auto_info" dtmf_mode in pjsip.conf. 
What I ran into is, that DTMF sent from endpoint A to endpoint B is additionally sent via inband audio on the RTP stream from Asterisk to endpoint B, as one can clearly hear the DTMF tone in the audio stream, when a capture is played back on Wireshark. On the leg from endpoint A to Asterisk there is no inband DTMF signal in the RTP audio stream.

Can someone confirm this behavior? If yes than this is clearly a bug.
I had a look in the code which introduced this feature and couldn't find anything obvious why this is happening.

 
 
With best regards

Florian Floimair
Innovation - Software-Development

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