Editing Telidon (section)

===Genesis===
Herb Bown is widely considered to be the "father" of Telidon.<ref name=b>[[#refBoyko1997|Boyko 1997]].</ref>  Bown had been working in the [[computer graphics]] field since the late 1960s, originally using [[plotter]]s but later moving to video systems. Starting in 1970, Bown and a team at the CRC started working on a "Picture Description Instruction"  (PDI) format to encode [[vector graphics]] information. An interpreter, the "Interactive Graphics Programming Language" (IGPL), read the PDI codes and [[rasterized]] them for display. By this time the team consisted of Bown, Doug O'Brien, Bill Sawchuck, J.R. Storey and Bob Warburton.<ref name=b/>

As the work continued, the team decided that locking the system to the particular hardware they were using was not appropriate, and started modifying the PDI system to be based on alphanumeric codes instead of binary numbers. A major advantage to this approach is that the data can be sent over common communications channels instead of relying on an [[8-bit clean]] link to the host computer. In 1975 the CRC contracted [[Norpak]] to develop an interactive colour display terminal based on the new alphanumeric PDI. The CRC had patented several of the technologies by the end of 1977; a touch-sensitive input mechanism, the basic graphics system, and the interactive graphics programming language.<ref name=b/>

By the mid-1970s several European countries were in the process of introducing videotex and teletext services. There was considerable interest within the industry, and in the media, suggesting that online services would be the "next big thing". Comments to the effect that "Within the next few decades, people may be able to access much of the published information in the world from their living rooms by using videotex,"<ref>Paul Muter, Susane Latremouille, and William Treurniet, [http://www.psych.utoronto.ca/users/muter/Abs1982.htm "Extended Reading of Continuous Text on Television Screens"], ''Human Factors'', Volume 24 Number 5 (1982), pg. 501-508</ref> were common in the trade press.

The CRC was able to interest the Department of Communications (DoC), their superiors within the federal government, to fund development of their system into the basis for a videotex service. Unlike the systems being developed in Europe and in Japan, the Canadian system would offer high-quality 2D graphics, higher speed, and could be used for one-way fixed or menued displays (teletext), two-way systems based on [[modem]]s (videotex), or they could combine the two, allowing information to be sent to the customer in the video signal, and returned via modem.<ref name=b/>