Teletext systems the country being closed captioning, TV Guide On Screen, and Extended Data Services (XDS). A version of the European teletext standard designed to work with the NTSC television standard used in North America was first demonstrated in the US in 1978 by station KSL in Salt Lake City, Utah, premiered a teletext service using Ceefax. They were followed by American television network CBS, which decided to try both the British Ceefax and French Antiope software for preliminary tryouts for a teletext service, using station KMOX (now KMOV) in St. Louis, Missouri as a testing ground. CBS decided on Antiope and
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