A device used to transfer digital information over analog telephone lines. Its most common application is to connect computer terminals or computers to other computers a great distance away. “Modem” is a word formed from “MOdulate/DEModulate.” Modems are characterized by their speed capability (baud rate), type (synchronous versus asynchronous), and compatibility with various hardware and software. Modems will no longer be necessary when the telephone lines used to connect computer systems operate in digital mode.