The word
modem, a
blend of "modulator" and "demodulator", refers to a device that modulates an
analog
"carrier" signal (such as sounds over a
telephone) to encode
digital information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Primarily used to communicate via telephone lines, modems can be used over any means of transmitting sound, from driven
diodes to
radio.
Different modulation schemes:
See also: Modulation