Unsupported Relay not triggering through 3CX

[Ollycuff]

Hello,

I have a Akuvox intercom on 3CX and I have programmed the key number 6 when pressed to release the relay on the Akuvox intercom. This was working up until I have introduced the SIP trunk and now it doesn't work but I have even restored my backup before I introduced the SIP trunk and it still doesn't work but it 100% did work. I have used another sip phone just a stand alone system and this works fine so the problem ls something to do with 3CX blocking the command.
Does anybody have any idea what I may have to do?

Thanks

Olly

 

[JohnS_3CX]

if I call the intercom with my mobile phone the relay will trigger by pressing 6!

The SDP 3CX sends contains the right type of DTMF, hence it appears to work when 3CX initiates the call.

but if the intercom call my mobile phone it doesn't work!

You will have to look at the SDP the intercom sends when it is the initiator. Comparing these two might reveal why it fails. You may have options in its UI to adjust this, until you get it working.

If possible, I would suggest using G.711U/A (aka PCMU / PCMA) as the top codec, and RFC2833 only as the DTMF type.