I thought I’d start this because I’ve been working on recovery of Teletext data from old Betamax tapes, and it seems to deserve its own thread. I’ve had some mild success with actually getting some readable data from the Seventext service off of a tape from 2 May 1984.
Before the internet there was Teletext. During the late 1980s and the 1990s it was a required accessory if you wanted the latest news, weather, finance, TV guide, TAB odds and results, and other information.
When I was in high school I loved to browse the catalogues of Brashs, Myer and other electronic retailers for TVs which had Teletext decoder.
I remember teletext but I didn’t realize if you recorded from the tv with a vcr that it got recorded too.
Man I miss the 80s/90s tv was such simpler back then.
The data was recorded on tape as part of the video signal (just above the start of the video frame), but the quality of recording was too low to actually permit decoding of the signal in real time with any reasonable quality. You can see the difference when comparing the video of decoding done in real time on a TV equipped with Teletext (the first video in my original post) and decoding the signal (not in real time) via a PC with a capture card (the second video in my original post).
It seems BTQ-7 produced the national service through to the end of Austext in 2009, with local inserts provided in each capital city. You can see that on the index page there was an ad for Commodore TV with offices in Sydney and Cooma, which seems to indicate that the 7Text service for Sydney and Canberra might have been combined. You can see there’s a structure where the news and weather are all carried in pages 100-199, general information (what’s on, traffic, etc.) on pages 200-299 and the TAB on pages 300-399.
Teletext was launched by TVNZ on 1 February 1984 with funding raised in the 1981 Telethon, to provide news and information for the deaf.
Teletext was initially based in Christchurch but, by 1991/92, had moved to Auckland (where TVNZ’s headquarters is currently located) until it was shut down in April 2013, although the television captions (for the deaf and hard-of-hearing) continued.
On 1 July 1985, Teletext in Vision replaced the test card which was shown for 15 minutes before the start of a typical day’s transmission across TV One and TV2 (now TVNZ 1 & 2). It was basically a 15 min selection of in-vision pages from Teletext, covering news, sport, weather and different kinds of information.
Here are some Teletext in Vision videos:
Monday 7 October 1985
Monday 17 October 1988
Saturday 21 April 1990
The kit BTQ used for Teletext was DEC PDP11’s and custom Teletext software from Logica in the UK.
The Teletext output was a low speed data stream(probably out of a PDP11 serial port) and it was put into the analog video signal by a Tektronics 148 VITS(vertical interval test signal inserter) on whatever lines it was supposed to go on. The same arrangement was also widely used when Closed Captioning came along during the analog TV days. As I recall there were a couple of PDP11’s that were used for editing and another PDP11 that was used for playout.
All leading edge stuff for early 1980’s.
