D-Link DVX-1000 User Manual page 25

Section  - Configuration
Contact - Specifies the contact for registration. Any SIP call to the user identified by User extension will be redirected
to this Contact value. Example: sip:9001@192.168.100.101.
Priority - Specifies the priority value for the contact. Priority value is a value between 0.0 and 1.0, with 0.0 indicating
least priority and 1.0 indicating highest priority. This is used to prioritize between contacts if more than one contact
exists for a user extension. Refer to Q Value in SIP RFC 3261 for more details.
Expiry Time - Specifies the expiry time for the registration. The registration would expire after the specified expiry
time. While adding a registration, Expiry Time is specified in seconds, whereas while displaying current registrations,
it shows the time and date at which the registration would expire.
D-Link DVX-1000 User Manual