you could take a look at call blocking and overrideshttp://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmeblock.html#wp1021929

thanks for getting back

can you clarify "device shows up on the server", what server is it and how does it show upyour phone is trying to retrieve a config file from either CME or CUCM, this config file contains, among other things, the line/extension number for the phone.I...