science · 17 January 1882 · 142 years ago
In 1882, a telephone switchboard was issued a U.S. patent to Leroy Firman of Chicago, Illinois (No. 252,576), which was assigned to the Western Electric Manufacturing Co. also of Chicago. With his invention of a “multiple switchboard for telephone exchanges,” Firman addressed the problem of increasing numbers of subscribers. Previously, single switchboards, each with an attendant, served their group of individual lines. A large exchange was thus divided up into a number of internal exchange switchboards which were worked together as necessary, with trunk lines between the boards. Firman devised an arrangement to handle an exchange of a thousand or more subscribers with line status information exchanged between switchmen.
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