Reference: http://www.cisco.com/c/dam/en/us/td/docs/telepresence/infrastructure/vcs/config_guide/
Cisco_VCS_Cisco_Unified_Communications_Manager_Deployment_Guide_CUCM_8_9_and_X7-2.pdf
Configuring the SIP Profile for phone devices This creates the SIP Profile that is to be applied to all phone devices.
1. On Unified CM, go to Device> Device Settings> SIP Profile.
2. Click Copy against the Standard SIP Profile.
3. Configure the following fields, leaving everything else a sits default value:

4. Click Save
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