A cable modem is a small electronic device that converts the broadband signal transmitted through your cable wiring into a signal your computer can recognize and utilize. A cable modem by itself cannot connect to more than one computer at a time. If you wish to have more than one computer connected to the cable modem, you will need to set up a router to split up the signal.
Unplug the cable modem from its power source. You will need to set up all the connections with the devices powered off for the connection to work properly.
Plug one end of the Ethernet cable into the "Out" jack in the back of the cable modem, and plug the other end into the "In" jack on the back of the router.
Turn on both your modem and your router and wait for them to power up completely.
Connect one of your computers to the router. There are two ways to do this: Either plug another Ethernet cable into your computer and into one of the router's "Out" jacks, or if if the router is wireless, connect to the router's Wi-Fi network using your computer's wireless card.
Open your preferred Web browser and type in the router's IP address, which is included in the router's documentation.
Configure the router according to the the user manual. Make sure you follow the steps carefully, otherwise the router will not work correctly.
Connect the other computer to the router, either by Ethernet or by wireless card, after the router is configured. The router will now provide Internet connections to both computers.
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