What happens if you have a DID set up in 2 different PBXes?

This will probably seem like a silly question, but please bear with me.

I have a FreePBX server being hosted (through RentPBX), and it’s set up with two trunks. I am also wanting to experiment with hosting my own FreePBX server.

I installed PIAF and seem to be rolling on my new, self-hosted server. So I backed up my RentPBX settings and restored them onto my own server.

This also backed up the two DID trunks I had, meaning for a period of time BOTH servers had the trunks registered and showed them as online.

That got me thinking… what happens in a case like this? Which one wins out? I’m probably missing something, because I’m sure this has happened before.

The whole reason for posting is because I have a problem – when I make outgoing calls on the new server, I get an “All circuits are busy” message. However, it shows that trunk as online, and I even disabled that same DID from the old server. I also am able to make internal calls on the new server.

So one question I have is what does happen when two servers try to register the same DID?

The other question is, any clue why I get the “All circuits are busy” message? I wouldn’t be surprised if it’s something extremely simple!

The registration timers on the servers are not synchronized so we will eliminate the possibility of both registering at the exact same time. As each servers register timer expires it will send out a registration message. Your provider can only send calls to one PBX so the last registration wins out.