Avaya 1210 User Manual page 71

Advanced features
Note: Some IP Deskphones are configured as Virtual Office-only
telephones and have no assigned DN. However, these IP
Deskphones can still be used to make emergency calls. "Emergency
Calls only " is displayed on the IP Deskphone display when not
logged in to Virtual Office. When the phone goes off-hook, dial tone is
available for emergency calls only. All other calls are restricted.
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