World System Teletext 653 (now ITU-R BT.653) as one of four recognised standards for teletext worldwide, and may now most commonly be referred to as CCIR Teletext System B. Almost all television sets sold in Europe since the early ’80s have built-in WST-standard teletext decoders as a feature. WST is used for all teletext services in Europe & Scandinavia, including Ceefax from the BBC and services from Teletext on ITV in the United Kingdom, ZDFtext from ZDF and ARDText from ARD in Germany, and Tekst-TV from NRK in Norway, among many other teletext services offered by other television networks throughout the European continent.
Teletext economic Teletext system with 1971 technology. However, as low cost was essential to the project's long term success, this obstacle had to be overcome. Meanwhile, the General Post Office (GPO), whose telecommunications division later became British Telecom, had been researching a similar concept since the late 1960s, known as Viewdata. Unlike Teledata which was a one-way service carried in the existing TV signal, Viewdata was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to drive more customers to use the phones. In 1972 the BBC demonstrated their system,