The Phelps Dual Magneto Telephone
U.S. Patent 209289--October 22, 1878
This dual Magneto Telephone was intended to be used as a transmitter. Phelps combines two or more diaphragms and magnetic cores into one " volcalizing-chamber" to increase the phone's output and to improve its articulation properties as compared to a typical magneto phone. The magneto did a satisfactory job working on short lines not subject to interference. As the lines became longer, though, higher output was needed. This design was able to achieve the maximum output from a magneto telephone and was used as an alternative to the carbon telephone transmitter. The above photo courtesy of the Smithsonian InstitutionGeorge M. Phelps |