In DVB (and IPTV systems that use MPEG TS) Teletext is sent in its own pid, along with the audio and video pids of the program being watched ( for the details you can check ETSI 300 472).
vlc btw contains a decoder for teletext pages, you can tune in to a dvb stream and look at them.
Trivia: in some countries (for instance in Switzerland) subtitles for movies are sent sometimes as semitransparent teletext pages (in CH it is on page 777) even if DVB supports natively subtitles.
I like this idea very much. I did the same reasoning regarding whatsapp and the likes. Mobile messaging is another use case that can be handled pretty well with email. We just need a better UI.
To toy around with the idea I created a prototype (still far from prime time but already working): http://www.carteggio.ch
vlc btw contains a decoder for teletext pages, you can tune in to a dvb stream and look at them.
Trivia: in some countries (for instance in Switzerland) subtitles for movies are sent sometimes as semitransparent teletext pages (in CH it is on page 777) even if DVB supports natively subtitles.