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
BBC news and sport station. In 1997, BBC News 24, a rolling news channel, launched on digital television services and the following year, BBC Choice launched as the third general entertainment channel from the BBC. The BBC also purchased The Parliamentary Channel, which was renamed BBC Parliament. In 1999, BBC Knowledge launched as a multi media channel, with services available on the newly launched BBC Text digital teletext service, and on BBC Online. The channel had an educational aim, which was modified later on in its life to offer documentaries. In 2002, several television and radio channels were reorganised. BBC Knowledge