DTMF - Force inband over RFC2833

[3CXDude]

Is there an option/way to force a V15 SIP trunk to use inband for DTMF instead of RFC2833 ??

 

[leejor]

That would be set in the DTMF Method options, on the originating set/device.

 

[3CXDude]

I need to try force it inbound on a trunk that hits a digital receptionist

 

[leejor]

I'm not aware of a setting allowing 3CX to modify the DTMF method. As far as I'm aware, it simply passes on whatever is sent by a device, be it a SIP message, or audio. You would have to try changing the settings on the set (and there are usually a number of option combinations) to see what works best in all situations.

 

[leejor]

Ah...you seem to be referring to incoming calls...that being the case...3CX should respond just about any method it receives. Audio DTMF doesn't generally "travel" well, when low bit rate codecs are used. You might have to "Wireshark" if you are having an issue.

 

[3CXDude]

Yeah I'm having intermittent issues with RFC2833 on a digital receptionist since upgrading to V15. Worked flawless on V14.

I was just hoping there might be a way to force inband from the 3CX side to test as a workaround.

 

[YiannisH_3CX]

There is no way to force the DTMF method received. 3CX will receive what is being sent by the provider. The preferred method of course is RFC2833. Are you using a supported provider? As leejor mentioned you might have to use wireshark to determine the issue on this one

 

[3CXDude]

No probs, that is what I suspected. I will have to see what options are available on the other end of the trunk.