I am running CUCM 6.1, with a MGCP 2821 QSIG gateway interfacing to a Samsung PBX. The originating caller-id is being prepended with a three digits number for certain calls that are transferred from a Samsung Phone to a Cisco Phone over the E1 link. So instead of seeing a four digit extension number ie. 4321, the originating caller-id is showing as 7764321. There are other seven digits originating caller-id numbers such as 5267185 that are being sent correctly, without the prepended numbers.
I would like to strip off these three leading numbers? I also need to be sure that digit manipulation is only performed on originating caller-id that has a leading 776
It appears that on CUCM digit manipulation can only be performed on calling and called numbers. Is the originating caller-id in this case the same field as the calling number? Would manipulating the calling number in CUCM change the originating caller-id?
Thanks in advance.