Presence
To activate Presence, select [Yes] from the drop-down menu . Furthermore, a contact must be created by activating the Presence, more on this under Presence contacts.
Busy lamp field
If your telephone system supports the busy lamp field, it must be activated here .
Validity range
The period of validity indicates the interval (in seconds) at which the telephone reports to the telephone system and announces the current status . [min. 300 max. 3600]