Using the same trunk for multiple DDIs

Previously, I had a VOIP account with, which provided me with 8 SIP accounts and 8 geographic numbers (DDIs).

In Asterisk/FreePBX, I set up 8 trunks to peer with these SIP accounts and 8 Inbound routes to send calls to 8 distinct internal extensions.

All worked well.

I recently asked to provide me with 8 more geographic numbers (DDIs).

They did this, but didn’t provide any more SIP accounts. They told me that I should be able to use my existing SIP accounts to route these new DDIs to new extensions.

I haven’t been able to do this.

Previously, when setting up my trunks, I used the following register string:

mxxxxx:[email protected]/1053


mxxx is the username
pxxx is the password
1053 is the internal extension associated with the DDI

The Peer Details are:

I then have a Internal Route, which is configured with the DDI and internal extension to ring.

In my VOIP settings, the DDI is configured to ring the relevant SIP acccount.

As I say, this all worked fine.

Can anyone point me in the direction of the changes I need to make so that different DDI can route to dedicated extensions via the same SIP account?

I have set up multiple Inbound Routes for the different DDI, but the DDI will always ring the internal extension in the Register String.

If I remove the internal extension from the Register String, the call doesn’t get placed.

I resolved this myself.

My Asterisk/FreePBX config is set up correctly, other than having to add:


to the Peer Details for the Trunk

After that it was a matter of setting up the correct routing in Blueface.

Previously, my geographic numbers were routed only to the SIP Trunk

3531555555 Ring SIP/siptrunk1

I change this so that they were routed to the SIP Trunk and the Inbound Route in Asterisk

3531555555 Ring SIP/siptrunk1/3531555555

All my geographic numbers can be routed into Asterisk via the same SIP Trunk.

The Register String does not need to be configured in any specific way.