Activating your Internet Connection
To play Call of Duty 4 online, you must first ensure your Internet connection is functioning properly. High-speed connections such as DSL and cable are preferable to dial-up Internet networks, as the higher data transfer rates DSL and cable provide reduce lag-time between user input and game response online against other opponents. To activate your connection, first make sure your router is correctly connected to your DSL or cable provider and powered on. An LED light, usually green, will indicate a working router and a connection to the Internet.
Connecting your Computer to the Internet
After establishing a working link to the internet from your router, you can then connect your computer to the network. Most routers are able to connect to computers either via physical ethernet cables or wireless LAN networks. Decide whether you would like to use an ethernet cable or a wireless network card to connect to the internet. A working connection will be indicated by your computer operating system's user interface. Once you are connected to the Internet from your own computer, you may begin playing Call of Duty 4 online.
Playing Call of Duty 4 Online
After satisfying Call of Duty 4's Internet connection requirements by activating your internet router and joining a network, you may then begin playing online. Double-check that both your Internet router and network connection (ethernet or wireless LAN) are functioning properly, and open the Call of Duty 4 Multiplayer ("MP") icon on your computer's desktop. Go to the "Options" menu and select your level of internet connection speed (DSL, Cable, T-1, LAN, etc.) and choose a username for your character ("Player 1" is default) before joining an online multiplayer game.