Denwa Communications DW-820 User Manual page 115

User Agent
Remote User Agent
ongoing call will be disconnected automatically once the
session expired unless it's been refreshed by UAC or
UAS.

Session Expire: Configure session expire time.

Session Refresher: To configure who should be response
for refreshing a session.
Note: UAC means User Agent Client, here stands for IP
phone. UAS means User Agent Server, here stands for SIP
server.
One can customize User Agent field in the SIP message; If
user agent is set to specific value, user could see the
information from PCAP. If user agent is not set by default,
user could see the company name, model number and
firmware version from PCAP
This feature need to be used with Auto Anser Doorphone
Delay. Go to the path: Phone->Call Feature.

Separator: Setup a separater, such as "," , "*"or "#" to
separate many door phone account.

Number List DoorPhone: Fill multiple doorphone number.