TELETEXT is a one-way, or non-interactive, system for transmission of text and graphics via broadcasting or cable for display on a television set. A decoder or microchip resident in the TV set is needed to extract the teletext information. Teletext can be transmitted over one-way cable or over-the-air broadcasting via radio or television. it is a closed loop of pages of information that are transmitted one after the other, over and over again. The viewer uses an on-screen index or directory to choose the pages of information to be viewed. A page number is then entered and, after a slight delay, the page is displayed on the television screen. Although teletext may appear to the viewer to be interactive, it is not. When one punches in a page number on a teletext decoder, the machine simply waits for that page to be broadcast, captures it and displays it on the television set.

In britain, where teletext was developed, two systems competed. CEEFAX was owned and developed by the b.b.c. and ORACLE was operated by Philips and Associated Newspapers, a British newspaper company.