Chicago Telephone SupplyChicago Telephone Supply1896–1960Founded in 1896 in Chicago by A.J. Briggs and his son George, the company moved to Elkhart, Indiana in 1902 where the city provided a factory building on a railroad spur. CTS focused on the rural telephone market, manufacturing magneto wall phones, switchboards, and notably building their own magnetos in-house. They produced approximately 175,000 telephones over 44 years, with the last phone manufactured in 1940. In the 1920s they pivoted to radio components, and during WWII developed precision potentiometers used in Allied radar. Still operating today as CTS Corporation in Elkhart, the world's largest variable resistor manufacturer. · Circa: 1896