Turlough O'Brien wrote:
"videotext" but there is little to no information available on the net about "Videotext" or in the libraries.I would greatly appreciate it if you could send me some informatin on the subject.
(This is from memory and unreliable) There was a proposed standard for North America called NAPLPS, for videotext presentation. I believe it was sponsored by Philips. If someone has a complete collection of BYTE magazines, I recall there was an issue devoted to videotext, circa 1981. The one clever feature of NAPLPS was that the graphics were based on floating point coordinates. Because screen sizes and resolutions would vary, positioning and sizing graphics was a problem. NAPLPS used a coordinate system where the width and height of the screen ranged from 0 to 1. For instance, to place a pixel in the center, you referenced coordinates (0.5, 0.5).
Videotext never really caught on in the US except on cable TV as a non-interactive display. I believe there are still a few videotext services piggybacking on satellite channels. They transmit on one of the unused scan lines at the top of the picture, similar to closed captioning for the deaf.
To my knowledge the only truly successful videotext implementation was the french minitel telephone directory.
Hope this gives you a place to start.
Jack Peacock
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Received on Fri Mar 20 1998 - 12:23:11 GMT