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<p class="MsoNormal">To FreeSWITCH Users,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have just noticed when making calls internationally to the UK from Australia that the following SDP sometimes happens when the call lands on FreeSWITCH:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d 2018-10-04 06:59:28.819816 [DEBUG] sofia.c:7301 Remote SDP:<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d v=0<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d o=sbc-uk-mr-dh05a 451499 139728 IN IP4 XXX.XXX.XXX.XXX<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d s=sip call<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d c=IN IP4 XXX.XXX.XXX.XXX<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d t=0 0<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d m=audio 62754 RTP/AVP 8<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d a=rtpmap:8 PCMA/8000<o:p></o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d a=ptime:20<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This then creates the following message around call answer: <o:p>
</o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">d5f14e47-2156-4236-be16-4eef1b7e9d3d 2018-10-04 06:59:28.839799 [DEBUG] switch_core_media.c:5766
<b>No 2833 in SDP. Liberal DTMF mode adding 101 as telephone-event.</b><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">From this point on DTMF is NOT detected by the FreeSWITCH IVR service. I assume I would then need to use mod_dptools: start_dtmf to detect the DTMF tones within the channel. Which I am yet to test.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">However my main question is whether there is a channel variable that would enable me to check whether 2833 support is not inside the SDP?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Andrew Keil <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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