Question : Problem: Configuring a WIC on a Cisco 1720

How do I configure a WIC on a Cisco 1720 Router for a T1?  It is not a serial WIC it is the RJ45 type.

Answer : Problem: Configuring a WIC on a Cisco 1720

Does it have two Ethernet ports? Generally, you get an Ethernet feed from a cable modem, plug it into one Ethernet port (most often WIC Ethernet module) set to obtain ip address via DHCP, and the other Ethernet port connects to your LAN (the onboard 10/100 FastEthernet 0 port).
If your WIC is WIC-1E, then it is 10BaseT Ethernet...