MODEM

A modem is used to transfer information through telephone lines. The term stands for modulate and demodulate which means to change the signal from digital, which computers use, to analogue, which telephones use and then back again. Modems are measured by the speed that the information is transferred. The measuring tool is called the baud rate. Originally modems worked at speeds below 2400 baud but today 14,400 is the minimum and speeds of 56,000 are common. Modems also use error correction that corrects for line noise on the telephone system by constantly checking whether the information was received properly or not and compression that allows for faster data transfer rates.