A
modem is a device that makes it possible for computers to
communicate over telephone lines. The word modem comes from Modulate
and Demodulate. Because standard telephone lines use analog
signals, and computers digital signals, a sending modem must
modulate its digital signals into analog signals. The computers
modem on the receiving end must then demodulate the analog signals
into digital signals.
Modems can be external, connected to the computers serial port by an
RS-232 cable or internal in one of the computers expansion slots.
Modems connect to the phone line using standard telephone RJ-11
connectors.
