Add TIM trunk without proxy configuration pending certification with

[andrea-marchionni]

The configuration for the TIM trunk requires:

• Provisioned phones should prioritize the G729 codec to propose it as the primary codec, and Nethvoice should ensure that this preference is propagated to the trunk as well.

• For an incoming call directed to an unregistered extension, a 6XX signal was received, which was formally incorrect. To address this, we made the following changes to the dial plan:

`
in macro-exten-vm it should set cause 20:

exten => _s-!,1,GotoIf($["${IVR_RETVM}"="RETURN" & "${IVR_CONTEXT}"!=""]?exit,1)
exten => _s-!,n,Playtones(congestion)
exten => _s-!,n,HangUp(20)

;exten => _s-!,1,GotoIf($["${IVR_RETVM}"="RETURN" & "${IVR_CONTEXT}"!=""]?exit,1)
;exten => _s-!,n,Playtones(congestion)
;exten => _s-!,n,Congestion(10)

`

• For incoming calls with an internal recipient (direct did), it was necessary to activate auto-answer on the route to ensure audio functionality during diversion. However, this caused an issue for calls directed internally, as the call was being answered before receiving an actual response from the internal recipient.

To resolve this, the macro-dial-one needs to be modified by adding the Answer() command in the extension related to the call forward (CF) as follows, prior to initiating the diversion

• To handle credentials with usernames in the format sip:XXXXXX@XXXXXX, it is not possible to configure the trunk name using the term "custom."
  Therefore, it is necessary to ensure that the proxy is not repopulated, even for the identity field.