ZyXEL Communications Prestige 2002 Series - Manual (Page 17)

Prestige 2002 Series
17
Specify phone numbers that should always use the regular phone service (without having to dial a
prefix number). Do this for emergency numbers (like those for contacting police, fire or emergency
medical services).
Specify the prefix number for dialing regular calls.
Use the Relay to PSTN fields to specify phone numbers to
which the Prestige always sends calls through the regular
phone service (without the need of dialing a prefix number).
These numbers must be for phones on the PSTN (not VoIP
phones).
Click Apply to save your changes back to the Prestige.
7 Dealing with NAT and Firewalls
A SIP Application Layer Gateway (ALG) is a NAT router that allows VoIP calls to pass through.
With a SIP ALG, you do not need to use STUN or do any extra configuration for the Prestige 2002.
STUN allows you to use a NAT (Network Address Translation) router between the Prestige 2002
and the Internet. STUN does not work with symmetric NAT routers or firewalls. If your ISP
provides the IP address of a STUN server, click VoIP and then Advanced to open this screen.
VoIPon Solutions www.voipon.co.uk [email protected] Tel: +44 (0) 1245 600560