media what died a'bornin'

[Tony Duell]

> In the U.S., the "closed caption" system, which is primarily for
> text for hard of hearing folk, puts two bytes of ASCII into line 21
> of the VBI (vertical blanking interval).  It CAN be used for other
> purposes.

This sounds very similar to the UK Teletext system (which is, indeed, 
used to provide subtitles for deaf people, along with many 'pages' of 
information). As I mentioned last night, this was used to distribute 
software for the BBC micro.

Interesting thing : The page number is a 3 digit BCD number, but nowhere 
in the hardware are the invald BCD nybbles (1010..1111) ever prohibited. 
Pages with such numbers can't be selected on a normal TV, but can be 
decoded and displayed by a computer-controller teletext decoder. And such 
pagesd certainly exist...

-tony