This might have been part of the Telext and Videotext technology that started up in the '60s and 70s and was generally well under way by 1981 - e.g., Teletex(t), Videotex(t), CeeFax, Prestel, Minitel, etc.
It seemed rather confusing, because it was a mish-mash of competitive, proprietary technology offerings.
I think Teletext became the de facto standard in UK/Europe, and
was (or maybe still is being
?) delivered via TV broadcast. (You saw "TXT" buttons on some TV remote controls if the TV had a Telext decoder fitted.) The data was carried for free in previously unused bandwidth (blank screen lines) in the TV transmissions. It was quite useful - e.g., on-screen updated information on things such as football results, weather, news, etc.
In the early '90s, something a bit similar seemed to have happened to Radio in the UK. The BBC was making digital radio information transmissions on FM, which could be utilised if you had a DR receiver. I recall hiring a car in the UK in the '90s. It had DR which could display transmitted information about the FM station (e.g., currently playing program name), and even brief traffic reports peculiar to your local FM transmitter's area. The reports appeared on a small car radio LCD display.
Bit dangerous if you were trying to read it whilst driving.
EDIT: Teletext is apparently alive and well, in NZ at least:
What is Teletext? TVNZ TELETEXT HAS IMPROVED(Link also contains a brief history of the development of Teletext from the '70s.)
