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 address of the BBC Engineering Information Department. The bulletin would then end with a rundown of the trade test colour films being shown on that particular day. ""And now we are returning to the colour test card and music until "Play School" at eleven o'clock"" would be a familiar closing phrase. "Service Information" bulletins generally lasted an average of two or three minutes but on Wednesday 25 August 1971, the longest "Service Information" bulletin known was aired, which ran for 11 minutes. A Monday to Friday "Tuning Information" bulletin was added to BBC2 in the heyday of colour coming to