9. Modem

A modem converts the digital data from the computer into a continuous analogue wave-form that the telephone system is designed to deal with (MODulation).  The reason for this is that the telephone system was originally designed for the human voice i.e. continuous signals.  The modem also converts the analogue signal from the telephone network back into digital data that the computer can understand. (DEModulation). Hence the word MODEM.

Standard ADSL modems come in two forms. An external box that links to your computer through an USB port or network cable, or an internal modem that is plugged directly to the motherboard inside the computer.

Wi-Fi modems

In addition to telephone modems, radio in the form of Wi-Fi is very popular as a means of connecting to the internet. The device that allows you to do this is called the Wi-Fi modem.