Things You'll Need
Instructions
Set up the DSL modem using the software that came with it. This step varies from service provider to service provider, so follow the model-specific instructions included with the modem. In most instances, you will need to hook up the modem to your computer.
Turn off the DSL modem and make sure the Xbox 360 is off. Most DSL modems do not have a power switch, so you must unplug them from the wall outlet to power them off.
Connect the DSL modem to your Xbox 360 using a Cat5 or Cat5e Ethernet cable. Modems only have one Ethernet port so you will have to disconnect any Ethernet cord from the modem before connecting it to the console.
Plug your modem back into the wall outlet to let it power back on. Wait for all of the lights to illuminate, indicating full power, and make sure it's connected to the Internet. Most modems have an "Internet" light that comes on when connected properly.
Turn on the console and wait for it to fully boot.
Press the "Guide" button on the controller and sign in to Xbox Live.