DTMF issues FreePBX 14 plus cisco CP-8941

Fresh 14 install with Asterisk 13.17.0. Cisco handset CP-8941 (SIP 9-2-3-5) everything up to date using CHAN SIP as that was how everything was setup before.

All working nicely except DTMF (re-install of setup due to borked upgrade) = i cannot manage voicemail or use remote menu systems.

The extension is set to RFC 2833 + NO nat + TCP preferred.

In the XML for the handset i have…


I cannot find info to make sense of the above statements so if anyone has a pointer or some suggestions as to how to get DTMF working sensibly with this handset and FreePBX i would be happy.

If you need any more config or trace details to understand what is happening - ask and i will collect what is needed.

Everything else seems to be working nicely, very happy with the handset(s).