For T1 circuits to an ISP, a T1 router is required to terminate the circuit and convert that connection to and Ethernet interface. This is sometimes referred to as a T1 modem or a T1 to Ethernet converter. The NetVanta series products can support this application when configured for IP routing. Internet Service Providers require that the unit which terminates an Internet T1 circuit be an IP router; ISPs will not allow bridging to the Internet.
A T1 router can be used to terminate an Internet T1 and provide an Ethernet connection to an external Ethernet firewall. All AOS based NetVanta routers have firewall capabilities and can be used as a T1 router with firewall to terminate a full or fractional T1 and hand off an Ethernet interface to the local area network.