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
Teletext hardware that could download pages of up-to-date news, reports, facts and figures targeting U.K. agriculture. The original idea was the brainchild of Philips (CAL) Laboratories in 1970. In 1971, CAL engineer John Adams created a design and proposal for UK broadcasters. His configuration contained all the fundamental elements of classic Teletext including pages of 24 rows with 40 characters each, page selection, sub pages of information and vertical blanking interval data transmission. A major objective for Adams during the concept development stage was to make Teletext affordable to the home user. In reality, there was no scope to make an