Thank you to everyone who helped on my previous post, I seem to unable to get that to work as I was expecting so maybe I'm looking at it from the wrong perspective. I'm starting a new thread as I believe this may be a different question/solution.
We have a SIP trunk that has lots of different numbers pointing to it. When we dial some of these numbers, the incoming call shows as it should (e.g. 01234 567890).
When we dial some of the other numbers, we get the 44 (e.g. 441234 567890)
I was hoping to be able to absorb the 44 and replace with a 0 but that didn't work out.
We've run a Wireshark trace and can see that on the incoming calls that display the incoming caller ID fine, the SIP header reads as:
From: <sip:01234567890@sip.provider;user=phone>;tag=xxxxxxxxxxxxxx
SIP from address: sip:01234567890@sip.provider;user=phone>
But on the calls that show the extra 44 information, the SIP header reads as:
From: "+441234567890"<sip:01234567890@sip.provider;user=phone>;tag=xxxxxxxxxxxxxx
SIP Display info: "+441234567890"
SIP from address: sip:01234567890@sip.provider;user=phone>
So, in essence, it's adding a 'SIP Display info' line to the header, then using the information contained within that to populate the 'From' header also.
So, is there a way to ignore the 'SIP Display Info' field and just use the number displayed in the "sip:01234567890@sip.provider" part of the header?