The Fantastic Teletext Coder

Have you ever wondered how the television broadcasting or retrieving the data? Well, they’re normally use a technique named “Teletext” or “broadcast Teletext,” where it’s a television information retrieval service developed in the U.K. in the early 70s.

Teletext offers a range of text-based information, where it’s mostly including national, international sporting news, weather and TV schedules. Majority of the subtitle information is being transmitted in the teletext signal on page 888!


Teletext information is usually broadcast in the vertical blanking interval between image frames in a broadcast television signal. It’s closely linked to the PAL broadcast system and most PAL television has been installed with a teletext decoder. Some of the common teletext services, such as TV schedules, regularly updated current affairs, sport news, simple games, and even the subtitles for deaf people in multiple languages!

Technically, teletext is uses a numbered page metaphor to present its information, all of which is broadcast in sequence. In this case, when a viewer keys in a page number, the receiver waits until that information is broadcast again in within a few seconds, and retrieves it for display on-screen. The best part about teletext is it can be seen as a predecessor of the World Wide Web, due to its presentation of user-requested graphic information, which makes it even cooler than internet!

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