Personal computer modem(1981)

Hayes simplifies the link between computer and the telephone system.

The devices which act as a automatic translator, altering the digitally stored information of a computer to analog tones transmittable over phone lines and, in parallel fashion, the incoming telephonic information to digital pulse for the computer is called modem. 

The first modems date back to the cold war and 1958, when the North American defense transmitted data over telephone wires to hundreds of radar station in the united states and in Canada . a modem has one essential function, which is to transfer the digital languages of computer into the analog language of the telephonic system and back again.

In 1981 Dennis Hayes launched the smart modem (originally named the Hayes stack smart modem). This was an automatic modem that for a time led the rapidly emerging personal computer market . earlier modems were not adaptable to a variety of computers, were expensive to produce, and variety of computer, were expensive to produce, and also were cumbersome to operate, requiring manual connection to telephone lines.

The brilliance of the smart modem lay in its ability to "think for itself" and programs inself into the telephone network . it did this by using its own data language to instruct itself to engage and disengage with other computers phone line according to the requirement of it's own operator. It also opened the way to cheaper and smaller design because, needing only data instructions from it's host computer it could be connected up to any computer by an easily accessible port.

By 1985 Hayes's company held nearly half the personal computer market and the them "Hayes compatible " had entered the language of computer as a benchmark against which to measure rival modems. The term was used to describe any modem that could claim to recognize the command sequence devised for Hayes smart modem.

The difference between the router and the modem is that the router is a small box that allow multiple computer to join the same network, whereas modem is the device that provide access to the internet