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
Channel Four Television Corporation service to provide schedules, programme information and features. The original service was called 4-Tel and was provided in collaboration with Oracle. In 1993, with Oracle losing its franchise to Teletext Ltd, the running of 4-Tel was taken over by Intelfax, and in 2002 was renamed FourText. In 2003, Channel Four awarded Teletext Ltd a 10-year contract to run an ancillary teletext service, named Teletext on 4, on a number of its channels. The service was provided on both Channel 4 analogue and digital television services, "Channel 4", "E4" and "More4". This has now been ceased and Teletext is no longer