ADC Telecommunications was a communications company located in Eden Prairie, Minnesota, a southwest suburb of Minneapolis. It was acquired by TE Connectivity (Tyco Electronics) in December 2010 and ceased to exist as a separate entity. It vacated its Eden Prairie location in May 2011 and moved staff and resources to other locations. ADC products were sold by CommScope after it acquired the Broadband Network Solutions business unit (including ADC) from TE Connectivity in August 2015. History In 1935, fellow engineers Ralph Allison and Walter Lehnert were each operating business efforts out of their respective basements; Ralph Allison was building audio amplifiers and Walter Lehnert was building transformers. In the fall of 1936, the two combined their efforts to form the Audio Development Company (ADC). The company was later renamed to ADC Telecommunications, Inc. During their first year in business, ADC built hearing aids and audiometers—a machine used for evaluating hearing acuity. Initially the audiometers were built for Maico, but in 1945 ADC began building audiometers under its own name. Additionally, by 1942, the company had designed a sophisticated audio system for the University of Minnesota, and the resulting jacks, plugs, patch cords and jackfields became the cornerstones for ADC's later entry into telecommunications. In 1949, ADC sold its audiometer product line and Ralph Allison left the company to form a new business in California. With Walter Lehnert remaining as president of the company, ADC diversified and focused its efforts in the area of transformers and filters for power lines, military electronics, telephone jacks and plugs. In 1961, ADC merged with Magnetic Controls Company, a manufacturer of power supplies and magnetic amplifiers with strong ties to the U.S. space program. The resulting company, ADC Magnetic Controls, had a decade of mixed success. Although transformer sales boomed during the 1960s, other new product initiatives failed to materialize. Perhaps the most significant product innovation during this period was the bantam jack, a miniaturized component that eventually became the standard for telephone circuit access and patching. Building on its growing sales of jacks and plugs in the early 1970s, ADC introduced prewired, connectorized jackfields, wired assemblies and test equipment for telephone operating companies. By 1974 the company was on solid ground, and by 1976, ADC had become the largest independent supplier of test boards in the United States. ADC grew in 1983, when AT&T was ordered to deregulate by the federal government. By establishing