Arthur F. Poole, an inventor from Wheeling, West Virginia, developed the harmonic selective telephone system in 1907. This invention addressed a significant problem with party lines, where multiple households shared a single telephone line. The main issue was that all phones on the shared line would ring simultaneously when a call came in, causing noise and privacy concerns.
Poole's harmonic selective telephone system solved this problem by allowing only the intended recipient's phone to ring. Each telephone on the party line was equipped with components that responded to specific frequencies or tones. The telephone exchange used machines capable of generating various tones. When an operator wanted to call a specific person on the party line, they would send a unique combination of tones. Only the phone tuned to that exact combination would ring, while others on the line remained silent.
This invention greatly improved the functionality of party lines by providing more privacy and allowing more efficient use of shared lines. Poole was granted U.S. Patent No. 1,070,726 for this invention on August 19, 1913.
During this time, Poole was associated with Mountain State Electrical (MSE) in Wheeling, a company that manufactured telephone and electrical equipment. While Poole collaborated with MSE on telephone-related patents, it's unclear whether they manufactured his harmonic selective telephone system. However, MSE did produce some of Poole's later clock inventions.
Poole's harmonic selective telephone system was a significant advancement in early 20th-century telecommunications. It enhanced the usability of party lines and contributed to the evolution of telephone systems, playing a part in the development of modern telecommunications.
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Photo credits: U.S. Patent Office