When third-party SIP phones get configured, the Cisco Unified CallManager database gets updated when the administrator uses Cisco Unified CallManager Administration. The administrator must also perform configuration steps on the third-party SIP phone; see following examples:
Proxy address in the phone should be the IP or Fully Qualified Domain Name (FQDN) of Cisco Unified CallManager
Directory number(s) in the phone should match the directory number(s) that are configured for the device in Cisco Unified CallManager Administration
Digest user ID (sometimes referred to as Authorization ID) in the phone should match the Digest User ID in Cisco Unified CallManager Administration
