The Bell Telephone Company was established in 1877 and produced the new invention, the telephone. The first telephone exchange took place in 1878 under license from Bell Telephone in New Haven, CT. For the first three years, telephone exchanges took place only in major cities in the United States, under license from the American Bell Telephone Company. In 1882, the Western Electric Company became the manufacturing unit of American Bell. Over time, the majority of its licensees acquired by the company thus became known as Bell System. On March 3, 1855, American Telephone and Telegraph became a wholly owned subsidiary of American Bell to build and operate the original long-distance telephone network. The AT&T was initially built in New York, followed by Chicago in 1982 and San Francisco in 1915. On December 30, 1899, AT&T acquired the assets of Bell Systems and became the parent company. Thanks to the inventions of charging coils, AT&T expanded into Colorado and, followed by the invention of the first practical electrical amplifiers in 1913, the company made going international possible. Bell's second patent expired in 1894...