BBC Micro depth, resolution and memory economy. In the first models, the OS and applications were left with the RAM left over from the display mode. Mode 7 was a Teletext mode, extremely economical on memory and an original requirement due to the BBC's own use of broadcast teletext (Ceefax). It also made the computer useful as a Prestel terminal. The teletext characters were generated on board, for use with monitors and TV sets without a Teletext receiver. Train time displays at UK stations were driven by BBC Master computers in this mode until around the late 1990s. Mode 7 used only
World System Teletext service and for a very short time by NBC in the mid-1980s. However, NABTS never became as successful as WST in the American continent, since NABTS was a more advanced technology, which required a much more complicated and expensive decoder (even though it had improved graphics capability over WST). World System Teletext World System Teletext (or WST) is the name of a standard for encoding and displaying teletext information, which is used as the standard for teletext throughout Europe today. WST originally stems from the UK standard developed by the BBC and the UK Independent Broadcasting Authority in 1974 for