49
SIP Operation Manual
VoIP failure announcement: As soon as VoIP call or the registration to proxy server is
failed, the gateway will drive IVR system to play out failure announcements for the caller.
Bind Proxy Interval for NAT: This function is able to keep the binding that exists when the
gateway is behind a NAT and Proxy Server is not able to keep the binding.
Initial Unregister: During the gateway start up, it sends UNREGISTER packet first to
release the possible invalid binding on SIP Proxy server.
Support Message Waiting Indication (MWI): Tick on the check box to enable voice mail
function. The system will play a tone to remind user if there are messages in the voice
mail.
MWI Subscribe Interval: The subscribe interval is for the gateway check of the voice mail.
NOTE: If you fail to make a call, please contact your Internet Telephony Service Provider.
OutBound Proxy Settings
An outbound proxy server handles SIP call signaling as a standard Proxy Server would. Further, it
receives and transmits phone conversation traffic (media) between two communication parties.
This option tells the gateway to send and receive all SIP packets to the destined outbound proxy
server rather than the remote gateway. This might help VoIP calls to pass through any NAT
protected network without additional settings or techniques.
NOTE: Please make sure your Internet Telephony Service Provider supports outbound proxy before
enable it.
Session Timer (RFC 4028) Settings
Session Expiration: It is used to avoid billing for abnormally dropped calls due to Internet
problems. The default is disabled.
Session Refresh Request: Used to resend UPDATE or re-INVITE requests to the server.
Session Refresher: Selects which user agent is the session refresher. UAS (User Agent
Server) is an originator, and UAC (User Agent Client) is a replier.
