many (like me) prefer to have the ATA (adapter) on the LAN side of the home router. This way, all home Internet traffic does *not* flow through the ATA. The home router connects to the cable/DSL modem as usual. The ATA's WAN port connects to a LAN port on the home router. Nothing connects to the LAN port of that ATA.

Some (few) routers need to have port-forwarding settings (virtual server) arranged for the LAN-side ATA. And a router setting for a DHCP reservation for the ATA so it's LAN address (like 192.168.1.x) is unchanging.