This problem occurs because the Cisco CallManager version 4.0 (1) and earlier does not support 7985G video phones.
To use the 7985G video phones, upgrade to Cisco CallManager version 4.1(3)sr2 or later. These versions of Cisco CallManager have the code necessary to support 7985G phones.
To download the upgrade, refer to Software Download.
Note: Make sure the minimum version requirements are met before Cisco CallManager is upgraded. For checking the requirements, refer to Cisco CallManager Compatibility Matrix.