The Glass Teletype
Sometime in the early 1960s, computer engineers realized that they could use CRTs as virtual paper in a virtual teletype (hence the term "glass teletype," an early name for such terminals). Video displays proved far faster and more flexible than paper; such terminals became the dominant method for interfacing with computers in the early to mid-1970s. The devices hooked up to computers through a cable that commonly transmitted code only for text characters -- no graphics. Until the 1980s, few supported color.
Photos: UNIVAC, Grant Stockly, DEC