Unusual software carriers. (Was :Vinyl Data- Classic Computers )

Roy J. Tellason rtellason at verizon.net
Wed Oct 1 23:02:38 CDT 2008

On Wednesday 01 October 2008 22:58, Jos Dreesen / Marian Capel wrote:
> In addition to radio and teletext, there was also a TV program in Germany
> that transmitted software by burying the data in the first few scanlines of
> the videosignal. The circuit to recover the datastream was quite simple.
> While the broadcast was running you would see a small box in the upperleft
> corner where you could actually see the data go by.

I've heard of all sorts of things being stuffed into the "vertical interval" 
but that stuff was not ordinarily visible onscreen,  unless you fiddled with 
the vertical hold adjustment to roll the picture a little,  and have the 
blanking bar showing.

I've also been curious for some time as to how one could "pick off" a specific 
scan line to get at whatever data was in there,  so if that circuit is online 
anyplace I'd be interested in taking a look at it,  even if it's not 
precisely the same thing.

Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

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