Modems are actually the shortened version of “modulator-demodulator.” These machines are crucial for getting Internet access. They help translate (or modulate) the digital signals of the computer into particular frequencies that are then sent through telephone or cable television lines. These frequencies are then retranslated (or demodulated) into digital form, which another computer can read. This is the method by which modems can communicate within a particular network.
Modems were used as early as the 1970s, when the computers were connected to what was called bulletin board systems. The modems were far slower, and the computers less powerful, then they are now. They could only communicate about 30 characters a second, by translating each digital bit (either 1 or 0) into tones.
Modem technology developed as people started sending programs and graphics. By the late 1990s, modems could send information at 56 kilobits a second. The Assymetric Digital Subscriber Line (ADSL) was even faster, and unlike the dial-up modem, it allowed people to use the telephone line simultaneous to surfing the Internet.
Another modem breakthrough was the Symmetric DSL (SDSL) technology, which allowed users to upload and download large files at the same time.
The other types of modems are the cable modem, which are often packaged with cable TV subscriptions, and satellite modems, which communicate via a satellite dish. However, satellite modems tend to be quite pricey, and the service is usually tapped by businesses or those who have no DSL or cable connections.
Modems are often packaged with internet services, though it is possible for people to purchase their own. It is important, however, to check whether the modem model is compatible with their internet service provider.