Videotex in its broader definition can be used to refer to any such service; including the internet, Bulletin board systems, online services and even the arrival/departure displays at an airport. In a more limited definition it refers only to two-way information services, as opposed to one-way services such as teletext.
The first attempt at a general-purpose videotex service were created in England in the late 1960s. In about 1970 the BBC had a brainstorming session in which it was decided to start researching ways to send closed captioning information to audience. As the Teledata research continued the BBC became interested in using the system for delivering any sort of information, not just closed captioning. In 1972 the concept was first made public, now known as Ceefax. Meanwhile the Post Office (soon to become British Telecom) was researching a similar concept since the late 1960s, known as Viewdata. Unlike Ceefax which was a one-way service carried in the existing TV signal, Viewdata was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to drive more customers to use the phones. Not to be outdone by the BBC, they also announced their service, under the name Prestel. ITV soon joined the frey with a Ceefax-clone known as ORACLE.
In 1974 all of the services sat down and created a standard for displaying the information. The display would be a simple 40x24 grid of text, with some graphics characters for constructing simple graphics. This standard was called CEPT1. The standard did not define the delivery system, so both Viewdata-like and Teledata-like services could at least share the TV-side hardware (which at that point in time was quite expensive). The standard also introduced a new term that covered all such services, Teletext. Ceefax first started operation in 1977 with a limited 30 pages, followed quickly by ORACLE and then Prestel in 1979.
Prestel was somewhat popular for a time, but never gained anywhere near the popularity of Ceefax. This was due primarily to it delivering much the same content, yet requiring the user to pay for the terminal (today referred to as a set-top box), a monthly charge, and phone bills on top of that (even local calls are paid for in most of Europe). Although Prestel's two-way features (including e-mail) were interesting, the end-users appeared to be unwilling to pay much for such a service, not as much as it cost to run it at least. In the late 1980s the system was re-focused as a provider of financial data, and eventually bought out by the Financial Times in 1994. It continues today in name only, as FT's information service.
Interest in the UK trials did not go unnoticed in North America. In Canada the Department of Communications started a lengthy development program in the late 1970s that led to a "second generation" service known as Telidon. Telidon split the data flow in two, using both the TV signal and the telephone. The TV signal was used in a similar fashion to Ceefax, but used more of the available signal (due to differences in the signals between North America and Europe) for a data rate about 1200 bit/s, while using a low-speed modem on the phone line for menu operation. The resulting system was rolled out in several test studies, all of which were failures.
Apparently unwilling to learn from these problems, a number of US based media firms jumped on the videotex bandwagon in the early 1980s. Unlike the UK however, the FCC refused to mediate in terms of a technical standard and each provider could choose what they wished. Some selected Telidon (now standardized as NAPLPS) but the majority decided to use slight-modified versions of the Prestel hardware. Rolled out across the country in 1982 to 1984, all of the services quickly died and none remained after another two years.
The primary problem was that the systems were simply too slow, operating on 300 baud modems connected to large minicomputers. After waiting several seconds for the data to be sent, users then had to scroll up and down to view the articles. Searching and indexing was not provided, so users often had to download long lists of titles before they could downloaded the article itself. Furthermore the much same information was available in easy-to-use TV format on the air, and didn't tie up your phone line. Unlike the Ceefax system where the signal was available for free in every TV, US systems cost hundreds of dollars
plus a monthly fee.
The Germans took the CEPT1 concept and expanded it so it was somewhat more flexible, the resulting standard was called CEPT2.
After that the French went one step further and developed CEPT3 that would be used for their popular Minitel system.
None of the CEPT standards used high resolution graphics.
For the French Minitel system, unlike any of the other services, the users were given an entire custom designed terminal for free. With its 1200/75 bit/s modem, users could dial various services and pay a per-use fee for the service itself, and one of the primary services was the phone directories. Soon Minitel was installed to the tune of tens of millions of terminals, and a whole industry was created to run Minitel services.History
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Minitel