- On Terminals - In the dark ages of computer times, computers did not have video screens and keyboards. There were computers, there were keyboards (typewriters), and there were video screens (televisions), but nobody had thought yet about combining them. Probably they were too busy to make computers work in the first place. The first computers used switches, lights and bells to communicate with their users ( and some modern old computers too ). But some time in the 50's, somebody thought that it might be nice for a user to actually be able to type in letters and numbers, and receive information in human-readable in return. Teletype Corporation was already making teletypes to let people communicate with each other in text over telephone lines. So through a serial connection, a teletype was interfaced to a computer, and from that moment on the user could tell the computer their opinion in plain text, and the computer could bang letters back on a piece of paper to hammer down what ...