A term that comes from a combination of MOdulate-DEModulate and refers to electronic equipment consisting of a device that is used to connect computers by telephone lines: A modem can be an Internal or external device that allows users to send and to receive data over telephone lines.

1. An electronic device that connects computers via a telephone line, allowing the exchange of information which consists of a modulator to convert computer information into a telephone signal and a demodulator to convert it back again. 2. A blend of modulator and demodulator.

• Modulator: A device that makes alterations in the characteristics of the amplitudes, frequencies, or phases of waves, or the velocity of the electrons in electron beams.
• Demodulator: The use of a nonlinear device in order to recover the original modulating frequencies, because these frequencies are not present in the modulated carrier and new frequencies cannot be produced by a linear device.