Date   : Wed, 25 Nov 2009 23:46:33 +0100
From   : rick@... (Rick Murray)
Subject: Teletext receiver revisited

Philip Pemberton wrote:

> What I wanted to know is what the other VBI lines are being used for. 
> The BBC are inserting a grey-level test on one line, so what's the other 
> stuff for? (it's probably not all Teletext data)

I think it can be for whatever. I remember seeing weirdness back circa 
Y2K on ITV prior to advert breaks. I guess it was some sort of "command" 
to tell local transmitters to switch to regional adverts.

You'd need to talk to a BBC bloke, and even then you might not get the 
full answer if it is test signals or something regional.

The once-a-second could be the TSDP?


Sadly all this stuff has been stripped from satellite in favour of the 
rather expansive BBCi (and similar) on a Sky box, or the rather cut-down 
  version on the FreeSat box... well... assuming your FreeSat receiver 
survived the recent balls-up of an upgrade [and here we can thank 
FreeSat for *not* supporting DiSEqC because I use my Goodmans box... 
hardly ever, it's the SL65 24/7!]

Anyway. Shame. It was a useful way to keep the computer's clock in sync 
in the days before wired connectivity. I now use time.nist.gov thanks to 
the default time.windows.com never syncing, but down deep inside I still 
miss the TSDPs.


Best wishes,

Rick.

-- 
Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...
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