science · 05 December 1879 · 145 years ago
In 1879, the first U.S. patent was issued for an automatic telephone switching system to Daniel Connolly of Philadelphia, Thomas A. Connolly of Washington, D.C. and Thomas J. McTighe of Pittsburgh (No. 222,458). The system consisted of a single-line wire, a battery of cells located at each telephone. and a dial switching mechanism for each line. Although this first system was crude in design and limited to a small number of subscribers, it introduced the general principle of later dial systems. The system, with eight stations connected, was exhibited at the Paris Exposition in 1881. The inventors made various modifications in subsequent patents. The system served a limited number of lines and was not introduced commercially.
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