Date   : Thu, 26 Nov 2009 01:38:32 -0000
From   : dm.hunt@... (David Hunt)
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)
> 
> A televisual equivalent of numbers stations?
> 
> </conspiracy-theory>

IIRC there were some remote pumping stations and sluice systems connected
via UHF to decode messages sent via the hidden VBI lines in Teletext. There
must be a mechanism to get your message transmitted.

Dave