I have a TrixBox Pro server as primary for the IP phones, but that does one IP, one number, so I had a a Trixbox CE (Asterisk at home) server set up to handle a couple of media gateways and a sip-dect cluster for some handheld phones. Server crashed hard, lost the hard drive, totally unreadable, and I am building a FreePBX to replace it. I have a sip trunk established between the two as I had done previously.
From the TrixBox, I dial a 9 + 5XXX string to reach extensions on the FreePBX, and they ring normally. When I call a 3XXX on the FreePBX, it comes to the Trixbox as if it where an outside call, and lands on the auto-attendant. If I dial the extension from there, it works like a normal call to the auto-attendant and goes to the extension. I have set up both dial out from the FreePBX using 9 + 3XXX for this and without dialing 9, with the same results.
Trixbox sets up every trunk as “incoming” context, but I have a script to change it back to “internal” any time they change it to keep the context set as internal, which was what I needed to do in the previous configuration.
My suspicion is that it is something in the TrixBox, which is an asterisk server with Fonality’s overlay on it, but to this point I have not been able to find it.