No ringback when forwarding offsite

General Help
1

When forwarding our office phones offsite/offnet, callers are not hearing any ringback tones. We are using Grandsteam 2140’s connected to Hosted FreePBX 2.8.1.5.

Carrier states:
They are passing us 183, however we are not passing audio to them until the called party actually connects.

Phone Support States:
Once the 2140 is set for forward it no longer would participate in
RTP. It would be the pbx that would need direct the RTP traffic and
build the signaling between the to endpoints in this case which would
not involve the 2140 during call forwarding.

We have made a ton of changes to the SIP trunk with no resolve. If anyone can assist that would be very helpful.

2

If anyone can help with this or has seen a similar issue I would appreciate it.

3

I have not encountered this and don’t know if it will work, but you might investigate setting:

 progressinband=yes

for the trunk.

4

Thanks lgaetz. I have tried that setting change to the trunk but it did not resolve the issue. Anymore thoughts would be appreciated.