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 Services (XDS). NABTS was originally developed as a protocol by the Canadian Department of Communications, with their industry partner Norpak, for the Telidon system. It was similar to the European World System Teletext (WST, aka CCIR Teletext System B), but differences between the European and North American television standards and the greater flexibility of the Telidon standard led to the creation of a new delivery mechanism that was tuned for speed. First demonstrated in the United States in 1978, NABTS was the standard used for both CBS's ExtraVision and NBC's very short-lived NBC Teletext services in the mid-1980s. Station KSL-TV