1. A law was passed making it a requirement for TV broadcaster to use
> some system of captioning and TV manufacturers to incorporate decoding
> circuits for captioning before Teletext took off in Europe. The US
> closed captioning system predated Teletext and it was a technical
> impossibility for a TV channel to incorporate both closed captioning and
> Teletext simultaneously. If the broadcaster decided to incorporate
> Teletext then all captioning would have to be on a Teletext page and
> that would mean owners of an existing closed captioning only TV would
> have to buy a Teletext TV if they wanted captions.
The US captioning system is NOT incompatible with teletext. Captioning uses only line 21; teletext (at least as implemented here) used a variable number of lines higher in the vertical interval - I want to say
13-18 but it's been a LONG time & my memory is probably wrong.
The teletext transmission standard is still used for private data transmission in the U.S.. The Canadian firm Norpak
formatting link
sells encoding and decoding equipment.
The law requiring caption decoders wasn't enacted until long after teletext failed as a consumer service. (but again that doesn't matter as it's possible to caption and run teletext at the same time)
2. The fragmented nature of the broadcasting industry compared to that
> of Europe gave little incentive for broadcasters to add Teletext pages
> to their channels unless there was a large enough audience with Teletext
> TVs. At the same time TV manufacturers were reluctant to add Teletext
> decoder circuits to all but their top of the range models because it
> would force up consumer prices. A catch 22 situation in other words and
> the government did not stick their fingers in to promote Teletext in any
> way.
That's probably the biggest reason.
3. Teletext was seen as pointless in the US because of the proliferation
> of dial up BBSs that emerged in the 80s prior to the internet. The BBSs
> offered a two way communications facility rather than the one way system
> of Teletext.
That's probably a significant reason too. Most U.S. telephone subscribers have unlimited local calling - a single monthly charge allows making as many calls in the local area as you want, and allows staying on the line as long as you want. I suspect this made BBSs more practical here than in Europe.
4. Teletext was developed for 625 line PAL systems and there was no
> standard developed for 525 line NTSC systems because of disagreements
> between various parties involved. The lack of a standard meant that
> broadcasters and TV manufacturers did not know how to proceed if they
> wanted to offer Teletext services.
There were two incompatible technical standards for teletext in the USA at that time. One was similar to that used for 625 PAL, the other claimed to have several improvements over the European system. (far better graphics, for one thing.)
The government made no effort to set a single standard. (Stereo AM/MW radio was introduced at about the same time - and it's widely believed the failure of the US government to set a single standard led to the failure of this innovation too.)