Cisco 1600 series routers connect small offices with Ethernet LANs to WANs through Integrated Services Digital Network (ISDN), asynchronous serial, and synchronous serial connections.The Cisco 1605 R router provides a 10BaseT and an AUI port on the first Ethernet interface and a 10BaseT port on the second Ethernet interface. The Cisco 1605 R router-which supports one WAN slot, two Ethernet ports, and the Cisco IOS Firewall Feature Set-makes anideal integrated and flexible firewall for small offices. This integrated router/firewall effectively segments an internal, secure LAN from aperimeter LAN exposed to an untrusted network (such as the Internet), thus creating a "demilitarized" zone.