Hi, I got a problem blocked me for 1 weeknow. The feature callforwarding (*72) is enabled. But having the extention e.g. 2101 (DID 55392101) have the call-forwarding set to a outside number e.g. 913959988320, and somebody calls from outside (number could be 137523298822) to extension 2101, it hangs up. But when the call from an internal extension, e.g. 2105 to 2101, it works! The cause has been identified that the ISP drop the call since the call ID was set to 137523298822, which is illegal. Is there a way to replace the caller id to the internal number, in my case 55392101 instead of 137523298822? Thanks a million! Lihua Xu.