Forhindrer at brukere endrer hvordan samtaler settes opp, enten direkte eller via en gatekeeper-server.
| Registry Hive | HKEY_CURRENT_USER |
| Registry Path | Software\Policies\Microsoft\Conferencing |
| Value Name | NoChangingCallMode |
| Value Type | REG_DWORD |
| Enabled Value | 1 |
| Disabled Value | 0 |