Create one extension for this carrier and I assume you will be IP authing it, do this in the extensions advanced settings where you can put a CDR to allow this.
Then create an outbound route for it and match based upon the sip_from_user. You can then use a regular regex match in the outbound route to remove the preselct stuff eg: for Cxxxxx something like ^C\d{5}(.*)$ and add the 44 prefix in the prefix box.
I'm also moving this thread to the general help section as this thread is for posting answers not questions.
Thanks again - ok so this carrier will potentially send maybe 20+ pstn numbers to our switch so i will need a sort of catch all from the ip ranges they have (already added to the acl as allowed CIDR), the only identifier we will have is that the number will be prefixed by our RID number so if our RID was C00123 the number appears as C00123441234567890@<ipaddress>
So if I'm understanding what you have suggested I need to do the following:
- Inbound destination will be incoming pstn number eg C00123441234567890 sent to the extension
- how then do i send anything to that extension to an outbound route that will strip the prefix off the front and send out like a normal sip route.
I'm not completely up to speed on the terminology so apologies if I'm not getting this straight away