[Technologist]

When Teletext ltd turned off their service …
There was a mass panic because the subtitles although being transmitted by the broadcasters
were not decodable by the viewers …..
So were they in breach of the requirement to subtitle ???
The broadcasters who had Ancillary text services had no problems !
As they had continuous teletext going out … Which (just about) kept the decoders happy.

After a few hours I think OFCOM told Teletext ltd to put something out
While the broadcasters sorted out what they should do.
I cannot remember what they did …..
but packet 8/25 or packets 30 or 31 are usually available in the inserters they were using
But the broadcasters were at fault !

There is /was not a decoder chipset in production from about 1980
Which can decode a compliant Teletext (EN 300-706 or 707 or 708) bitstream
That is not continuous.
So professional kit like DVB encoders (TXT and TXT to ST )invision monitors ,data bridges etc
all had means of decoding intermittent text ….

Actually I think something similar happened on Radio 4 LF when the electric signalling stopped due to,a fault
A particular model of flood siren went off …. As it was designed to do if it lost data.