[Freeswitch-users] DTMF

[Brian Chamberlain]

Hi All,

Is there a way to detect the dtmf mode on a leg of a call?

At the moment we have a carrier who sometimes sends inband and sometimes sends 2833, sometimes proposes 2833 but only sends inband, etc...

I've set dtmf-type on the profile in use with this carrier as none so whenever we send 183 or 200 freeswitch doesn't have any telephone-event in the SDP and the carrier sends inband. Its the only way I could guarantee consistent DTMF mode with this carrier.

I have most cases worked out but I have an edge case where a customer is using a REALLY old PBX and needs inband and not 2833

When we send a call to this customer we offer 2833 in the proposal and the PBX sends back that it doesn't want any DTMF signalling which is correct.

Unfortunately because I'm calling spandsp_start_dtmf even though there is no proposal from PBX freeswitch sends DTMF from carrier INBAND but also generates SIP info messages. This gives the dreaded double digit issue.

If I comment spandsp_start_dtmf everything works great but I need spandsp_start_dtmf .

Is there someway to detect that the dtmf-type is none on a channel and in that case don't call spandsp_start_dtmf or detect 2833 and do call it?

I've been looking for variables I could check but can't find one..

I could drop these messages on our proxy but would prefer if there was a more elegant solution.

Many Thanks for any assistance.

Regards
Brian

 		 	   		  
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