teletext

Teletext is a data broadcasting service that delivers text and simple graphics alongside television programs by transmitting information in the vertical blanking interval of analog TV signals. It originated in the early 1970s in the United Kingdom, with BBC’s Ceefax and the commercial Teletext services operating alongside other European implementations. The system spread to many countries and became a widely used method for delivering news, weather, TV schedules, and other pages of information to home receivers.

Pages are accessed by entering a three-digit page number on a compatible TV or set‑top decoder, or by navigating with remote controls. Teletext pages are organized by topics such as news, weather, sports, and subtitles, and are presented in a fixed, text-dominated format with simple color and graphic capabilities. The typical page layout used about 24 lines of text and up to 40 characters per line, with a limited palette and basic block graphics.

Technical standards for Teletext were developed under the World System Teletext (WST). Information is encoded in a 7-bit character set, and pages include control codes for formatting, color, and navigation. Subtitles for television programs were a prominent feature, providing access to dialog text for the hearing impaired.

With the transition to digital broadcasting and the adoption of new subtitling standards, traditional analogue Teletext declined through the 2000s and early 2010s. Some broadcasters retained Teletext as a legacy service or for compatibility with older equipment, while others migrated to DVB subtitling and on-demand delivery. Teletext remains a notable chapter in the history of broadcast information services.