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 London BBC London BBC London is the BBC English Region producing local radio, television, teletext and online services in London and parts of the surrounding area. Its output includes the daily "BBC London News" and weekly "Sunday Politics" on television, the BBC Radio London radio station and local coverage of the London area on BBC Online and BBC Red Button. The region's headquarters are situated in the new eastern extension of Broadcasting House. The staple of the local television service is BBC London News which broadcasts daily on BBC One, appearing with short bulletins during "BBC Breakfast", after the "BBC News