I have a central PBX which is connected to a remote office via a dedIcated VPN trunk. This trunk is set to “InterOffice” which means the 3-digit Extension CID is preserved when calls are routed to the Central PBX. This allows the extension CID to be displayed on all internal calls.
However, a call placed in the remote office to a public (Outbound) number, will also be routed to the Central PBX which will then execute the outbound call via its Outbound Route dialplan and associated Outbound Trunk.
The Outbound Route is set as follows:
Route CID: 0xxx xxx xxxx (redacted numbers)
Override Extension: Yes
However, the Extension CID from the remote office is still being passed to the trunk, which then sends this to the SIP Service provider when the Outbound Trunk is set to “Allow Any CID”.
A temporary workaround is to force the Route CID on the Trunk, however this overrides all other CIDs except Emergency CIDs, including foreign CIDS from forwarded external calls.
Confusingly, the Force Trunk CID Help says:
“Intra-Company Routes will always trasmit an extension’s internal number and name.” However, this does not seem to be true when Force Trunk CID is selected, as the Trunk CID is then used.
It would seem, in fact, that the remote office Extension CID is not being treated as an extension, even though “InterOffice” is selected, which would seem to be the more logical behaviour. Instead, it is being treated the same way as foreign CIDS from forwarded external calls. I would have anticipated that a trunk designated as “InterOffice” should not be treated as an external call and should be regarded as an extension for CID purposes.
Can someone please kindly advise if there is a better or recommended way to set this up so that the Route CID is used on Outbound Calls when originating from the remote office.