I dont think so. I have tried with it and cant change it. So when the call goes out to the cell phone, the caller ID is the calling number. I know telepacific carrier does not accept this on their broadcom softswitch. It has to be a DID on their trunk or gets rejected. Drives us nuts because we cant change the number or we could, but then other items would not work. (caller ID from the IP phone) We could mask all numbers, but ....