I have a Cisco 7961-G-GE IP Phone that will not regsiter with Call Manager. It shows that it is registered in Call Manager but does not show any Directory number on the Phone display. I did the factory defaults and still no luck. It has the latest firmware. I can access the corporate directory and Services from this phone.
PS: This phone is in remote office and connects through VPN tunnel. I have a 7960 Phone that works fine over the VPN.