[asterisk-users] RFC4733 (2833) payload during early audio 183?

Benoît Panizzon benoit.panizzon at imp.ch
Fri Apr 17 03:39:59 CDT 2020

Hi Gang

Not a specific Asterisk Question.

But I wonder, if the called party replies with 183 + SDP indicating
support for telephony-event.

Should the caller be able to send DTFM Tones?

Swiss Railways uses an IVR that kicks in before the call is answered.

So far I have found no SIP Phone which would allow sending RFC4733
during the early audio phase (so I cannot test if Asterisk
would forward them) rendering the IVR unuseable. But the RFC itself
suggests that there is no restriction on which SDP (183 or 200) the
telephony-event is announced.

Mit freundlichen Grüssen

-Benoît Panizzon- @ HomeOffice und normal erreichbar
I m p r o W a r e   A G    -    Leiter Commerce Kunden

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