A broadcasting service that transmitted text to a TV set with a built-in teletext decoder. Introduced in the 1970s in the U.K., the text was transmitted in the vertical blanking interval between frames of the TV signal. Teletext was occasionally used in the U.S. and Canada but never really caught on. It was also used in Australia until 2009. Elements of teletext are still used for closed captions.
A Rotating Rolodex
Different kinds of information such as news, finance and weather were displayed in a series of continuously rotating teletext frames, which could be selected from a program guide. See vertical blanking interval
, closed captions