We interrupt your scrolling with an important message. These are the different standards for videotex, a protocol somewhere inbetween teletext and internet.
It wasn’t all pure text-mode. Videotex also had vector graphics and the ability to change fonts, and plenty more things. Telidon was perhaps the most widely used videotex standard, or so it seems today.
Not sure if they ever got around to a world standard, like they did with teletext (which was a techno-battle between France and the UK).