A Modem is what allows your computer to communicate with the outside world. It is most commonly used to connect computers to the Internet, but can also be used to communicate directly with another computer.

There are two types of modems that are currently in use, Dial-up modems which connect computers via a phone line; and Broadband modems which have a high-speed always on connection to the internet.

Most people still need a dial-up modem to connect them to the internet. All current dial-up modems for sale today are rated to transfer information at 56k a second. Make sure your modem is V.90 compatible, It almost assuredly is but make sure anyways. Dial-Up modems are either internal in card form, or external, hooking up through your USB or Serial Port. Internal modems are the more popular of the two, as they are cheaper and take up less valuable desk space. If you opt for the internal modem make sure it is of the PCI variety. ISA cards are just too much of a headache to justify their usage for any reason whatsoever. Try not to get a winmodem if at all possible. A winmodem uses some of the computers resources to perform its functions, this not only slows down the system, but also can potential to create conflicts within the system. They are considerably cheaper however, and if money is a real issue then get the winmodem and keep your fingers crossed.

The other option is a cable or DSL modem. If you have cable or DSL service then your installer will in all likelihood provide you with the necessary modem. This is usually an external modem that hooks up to either your network card or your USB port. If you do not have cable or DSL service than your cable or DSL modem will not work on your system (although it might make a nice paperweight)