The Early Teletype Monitor
Prior to the invention of the electronic computer, people had been using teletypes to communicate over telegraph lines since 1902. A teletype is an electric typewriter that communicates with another teletype over wires (or later, over the radio) using a special code. By the 1950s, engineers were hooking teletypes up to computers directly, to use them as display devices. The teletypes provided a continuous printed output of a computer session. They remained the least expensive way to interface with computers until the mid-1970s.
Photo: Systems Engineering Laboratories