Cisco 7925G Deployment Manual page 67

Once the certificate is installed successfully, a confirmation page will be displayed.
The CA chain should already be enabled in the authentication server's certificate trust list.
The authentication server certificate must also be imported into the Cisco Unified Wireless IP Phone 7925G for both methods.
If the authentication server certificate was signed by a Certificate Authority (CA) server, then that DER encoded root certificate
will need to be imported into the Cisco Unified Wireless IP Phone 7925G.
If the Cisco Unified Wireless IP Phone 7925G has not registered to a Cisco Unified Communications Manager yet, then the date
and time must be configured manually for the first time.
Cisco Unified Wireless IP Phone 7925G Deployment Guide 67