Inauguration of New National Meteorological Teletype System - 1969

Ontario Weather Centre - Toronto International Airport

left Hon. Don Jamieson, Minister of Transport; right J Reg H Noble, Head Meteorological Service of Canada.

More Information:   In 1969, the Meteorological Branch, Department of Transport inaugurated its new national teletype system. In contrast to the previous teletype network, which had been based on manual, torn-tape switching and distribution of message traffic, the new system, operated on behalf of the Meteorological Branch by CNCP Telecommunications, was completely computerized, using CNCP's dedicated Collins C8500 message switch located at 151 Front Street West in Toronto. The Met Branch was a very early adopter of the new computer switching technology, being only the second corporate customer of CNCP's automated offering. The change to the new network was also marked by the transition from the 5-level Baudot character code to the then relatively-new 8-level ASCII code (the American Standard Code for Information Interchange), with most collection and distribution circuits operating at 110 bits per second ("110 baud" -- 10 characters/second, 100 words per minute).

The machine shown was typical of the new terminal equipment installed at Met Branch sites across the country. This was the Teletype Model 35 ASR (typically referred to as an "ASR-35"), with "ASR" identifying it as being capable of "Automatic Send and Receive". The ASR-35 included a keyboard, a printer, a paper-tape punch ('perforator"), and a paper-tape reader ("transmitter/distributor"). Messages were prepared for transmission by being punched onto paper tape from the keyboard. The tape was then set in the reader and was read in for distribution by the computer message switch when the appropriate "poll" character sequence was received and identified by an additional piece of equipment known as the "selector", which automatically started the reader.

The ASR-35 was a completely electromechanical device -- no electronic components were employed, just an extremely complex system of motor-driven gears, shafts, cams, and levers. A lighter-duty (and less-expensive) version, the ASR-33, became well-known as the standard console for small computer systems throughout most of the 1970s..

credit: John Botari

Return to Index