Teletext and to pad out the fixed packet. The vertical caption position is determined by the packet address. In the case of the Ceefax and ORACLE systems and their successors in the UK, the teletext signal is transmitted as part of the ordinary analog TV signal but concealed from view in the Vertical Blanking Interval (VBI) television lines which do not carry picture information. The teletext signal is digitally coded as 45-byte packets, so the resulting rate is 7,175 bits per second per used lines (41 7-bit 'bytes' per line, on each of 25 frames per second). A teletext page comprises
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