I am looking for a way to have a remote extension of our PBX using the Internet. If I buy a MultiVOIP to connect to our PBX, can I then connect to the VOIP using an IP Phone?

IP phone<>NAT firewall<=>internet<=>MPV200<=>Analog Port on our PBX

The MultiVOIP will work with IP phones as long as your router supports H.323, and the IP phones are true H323 phone and do not require a PBX to register to. Welltech has an IP phone that has been proven compatible with the MultiVoIP.