The story of Pye Canada should not be told without briefly reflecting on the story of Ajax. When Britain declared war on Germany on September 3, 1939, with Canada following suit within one week, the site where Ajax is situated was farmland with fewer than 200 people living in the area. In the search for a location to build a munition plant safely out of the reach of enemy planes, Britain looked to Canada. The site just to the east of Toronto in the former Pickering municipality met all requirements. In short order farmers were expropriated and plans drawn up for what was slated to become the largest shell-filling plant in the British Empire. To manage this undertaking and similar projects in Canada, Defence Industries Limited (DIL) was founded. By the end of June 1941 partial operation started. Towards the end of the war the number of workers on this location had swelled to more than 9000 men and women. With that many people working and living in the area, the place obviously needed an address. A competition among DIL employees resulted in the name Ajax being chosen, in honour of one of the three British warships that in 1939 had engaged the German pocket battleship Graf Spee at the battle of River Plate. Following the end of World War II, the Government of Canada was undecided about the future of the large munitions complex in Ajax. Eventually it was decided that rather than returning the land to farming, the plant, with its six hundred wartime homes and six abandoned production lines, could be the nucleus of a fully planned model town. To carry out this plan would require an influx of industry to create employment for the resident and to provide a solid taxation base. The initial policy was to attract industry from Britain, the mother country. In 1950 Slough Estates came to Ajax and purchased a block of industrial land. Hunt Capacitors of London, England, was one of the first tenants in that industrial park. Even before that, PYE Ltd. of Cambridge, England, had chosen Ajax as its Canadian base. The following is an excerpt from "A Town Called Ajax", with the friendly permission of the Ajax Historical Board. Pye Canada Ltd. Was incorporated as a wholly-owned subsidiary of Pye Ltd. of Cambridge, England. Pye Ltd. was a national leader in electronics in the United Kingdom, designing and manufacturing everything from simple battery radios to sophisticated radar equipment.

At the end of World War II Pye decided to expand and develop its overseas markets with manufacturing plants in Australia and Canada. A search was undertaken for a suitable area in which to locate such a plant in Canada. Industrial areas were examined in most provinces, with Ajax being chosen because of its access to highway and rail transport, and availability of labour. It was also close to the large Toronto market and the U.S. border. In addition there were a number of available DIL buildings from which to choose a manufacturing site. In 1948 the company negotiated with Central Mortgage & Housing Corporation for acquisition of a large warehouse building on the southeast corner of First Street (now Hunt Street) and Avenue B. (now Monarch Avenue). This building was chosen because it had a reinforced floor which would support the heavy machines used to manufacture the metal chassis in which the radio receiver assemblies were housed. The building was still in use by the University of Toronto as a lecture hall for the engineering faculty, but would soon be vacated, as the Ajax campus was to be closed in 1949. Pye Canada Limited was incorporated in 1947 with its official business address in Ajax. The process of purchasing the equipment to be used in manufacturing by Pye Canada was begun. Assembly benches were also ordered, as well as the necessary office equipment. These preliminary preparations were under the direction of George Greenep, who became the first Managing Director of Pye Canada. When the building became available, the installation of equipment and offices got underway. Local residents were hired to staff the plant and 1949 saw the production of the first radios. Their design was essentially British, with modifications to qualify for approval from the Canadian Standards Association (CSA). To make the technical changes necessary to secure CSA approval, an Engineering section had to be stationed within the plant. This section would become an important factor in the following years, developing many products and systems that were marketed throughout Canada and the United States. As plant production increased the workforce surpassed one hundred persons in 1950. About this time George Greenep returned to the parent company because of poor health, and was replaced by Bill Jones, who then headed the company until 1960. This was a period of growth, and a second building was purchased on Avenue B. This was a two-storey structure, and the company used the lower floor for storage. The second floor was for company get-togethers, dances and other social affairs. A smaller building which was attached to the warehouse became an employee clubhouse. It was here that the Ajax Dart League had its beginning. This small building was later moved, and joined to the manufacturing plant to increase office space.

In 1952 Pye Canada began marketing two-way radio systems to police forces, fire departments, taxicab companies and others. Among their customers were the Ajax Fire Department and the Pickering police. During the 1950s the company opened offices in Winnipeg and Vancouver in the west, and Montreal and Halifax in the east. An office was also opened on Front Street in Toronto. When television made its debut in Ontario, Pye set up a line for television production. They also obtained government contracts to supply amplifiers and sonar equipment for the Royal Canadian Navy. Next they designed a telemetering range equipped to monitor ground-to-ground missiles for the Armed Forces at Nicolet, Quebec. The first mobile television units were made for CBC by Pye Canada. These were used during the Commonwealth Games in Vancouver. Underwater camera work was carried out by Pye when they received contracts to produce underwater programmes for the "Wide World" series on the NBC network in the United States. In addition, the company was under contract to NASA to recover test missiles off Cape Canaveral. Their cameras were also used in checking underwater natural gas well heads. Pye Canada TV and underwater cameras and associated products became widely known, and were sold throughout North America.

Other products marketed by the company included sensitive scientific equipment, electronic test instruments, loud hailers and fish finders. As the industrial section of Ajax grew, several electronic manufacturers located there. This resulted in a Department of National Defence Inspection Service being set up in the Pye plant to provide services to electronic firms in the area. Hunt Street was still unpaved at that time, and passing vehicles raised much dust. Penetration of dust into the inspection areas could impair the performance of the supersensitive inspection instruments. Faced with the threat of losing profitable government contracts Pye moved its main operation to a building with controlled atmosphere in East York. A technical office was maintained on McMaster Avenue in Ajax until 1968. At that time the parent company was bought by Philips of Eindhoven, Netherlands, and the Canadian plant was consolidated at the Philips plant in Scarborough. Many of the original Pye employees were employed by the Philips company.