Modem

Modem, an acronym for modulator/demodulator, is a device that allows one computer to "talk" with another one over a standard telephone line. Modems act as a kind of interpreter between a computer and the telephone line. Computers transmit digital data, expressed as electrical impulses, whereas telephones transmit voice frequencies as analog signals. To transmit digital data, the sending modem must first modulate, or encode, a computer's digital signal into an analog signal that can travel over the phone line. The receiving modem must then demodulate, or decode, the analog signal back into a digital signal recognizable to a computer. A modem transmits data in bits per second (bps), with the fastest modems transmitting at 56K (kilobits per second). An internal modem is housed within the computer itself, while an external modern is a separate device that is connected to the computer via a cable.