Device used by your personal computer to negotiate dial-up networking protocols. A modem transforms the analog data it gets from a phone line into digital data that the computer can understand. The faster the modem the better, with modems of 56k and upwards being required to run web browsers and Internet applications at good speeds. With the implementation of broadband lines in the UK, you can now buy cable modems that run about 10 times the speed of a regular phone modem.