First you have to decide on a system. BCM 200 & 400 support VoIP. Lots to know when dealing with Network provisioning for this stuff. If you have a good data background great, you'll fly by on the Q.O.S. needs, types of routers, switches and Bandwidth requirements etc.... BCM is your only true VoIP system in the Norstar family that allows you to have off prem. sets and locations acting as one seamless office. The gateways are good for cutting long distance and tying in offices via intercoms or CO ports. Example office in Canada has a Mics with a 2 port gateway, office in US has a CICS with a 2 port gateway. Canada uses two ATA signals in it's gateway in the "OUT PORT" goes on the LAN, hits your data network, over the Internet, i n reverse motion on the US side now. From Network to LAN to Gateway and these will terminate on the US side as the "IN PORT". Now put them on a CO Port let's say 003 & 004. So now you can intercom Canada from US using line assignment #'s 003 & 004 and Canada to the US using the approp. Intercom # of the two ATA's. Remember all the same QOS and Bandwidth stuff is still in effect here, just not as much pending on the size of your gateway. Later!