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 to four lines a frame. While the basic teletext format has remained unchanged in more than 30 years, a number of improvements and additions have been made. A closely related service is the Video Program System (VPS), introduced in Germany in 1985. Like teletext, this signal is also broadcast in the vertical blanking interval. It consists only of 32 bits of data, primarily the date and time for which the broadcast of the currently running TV programme was originally scheduled. Video recorders can use this information (instead of a simple timer) in order to automatically record a scheduled programme, even