I am trying to connect several Cisco SPA-501G handsets to our 3CX v10 PBX (licensed). We have the 3CXPhone working fine on the PCs, and the iOS phone working fine on our iPhones, but can not get these damn Cisco phones to work properly. They will receive calls fine with no issues whatsoever, the problem comes when trying to make out going calls. You lift the hand set and you hear a dial tone. You dial the number (either internal or external) and it just sits there waiting for you to input more digits. Eventually it just gives you the number not in use type tone. The phones are local to the PBX, same subnet, same group on network switches. Has anyone else had issues when trying to make out going calls from an IP phone? Anyone have any ideas what the issue may be? any advice welcome!