When Cisco VT Advantage and 7970 phones are connected to a PC and configured on the Cisco CallManager server, VT Advantage shows unconnected (broken red line) between the 7970 phone and the PC.
The show ephone reg command shows that the phones are only in audio mode and do not have the "+Video" capability. For more information about Cisco Unified Video Advantage, refer to Overview of Cisco Unified Video Advantage.
Under Telephony Service, the service name must be configured as service phone videoCapability 1. This is a case-sensitive service name so any deviation in the service name results in the error. For more information, refer to Troubleshooting Cisco Unified Video Advantage.