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
Service Information Service Information Service Information was a regular programme in the early days of colour television in the United Kingdom that gave out engineering information for the radio and television trade. These announcements were made by the BBC continuity announcers of the time and were read over in-vision captions. The programme was broadcast on BBC2 three times a day, 10.00am, 11.30am, and 2.30pm each weekday from 23 October 1967 to 1975, then once a day at 10.30am from 1975 until the final broadcast on 23 December 1982. The IBA (and its predecessor, the ITA) had a similar programme titled "Engineering Announcements",