Modem, << MOH duhm or MOH dehm, >> is a device that enables computers to transmit and receive information over the telephone network. The word modem stands for mo_dulator-_dem_odulator. A modem _modulates (translates) a computer’s digital electrical signals into tones that can travel over telephone lines. A modem at the other end demodulates (retranslates) the tones back into computer information. Modems can send and receive not only text information but also sound, still pictures, and moving pictures.
Modems and telecommunications software make it possible for computer users throughout the world to communicate with one another. To begin this communication, a modem first sends a signal representing a telephone number. The telephone network directs the transmission to the device represented by that number. Communication can take place directly with another computer’s modem, or via the Internet (see Internet ).
The faster a modem works, the easier it is to receive complex information. Modem speed is measured in units called bits per second (bps). A special type of modem known as a cable modem is used to link a computer to a network over cable television lines. Cable modems transmit data much faster than telephone modems do.
