A New Telephone Relay and Its Applications ¹

Abstract

EVER since the introduction of the telephone a real need was felt for a telephone relay, for the distance over which telephones could be used was found to be comparatively limited. Edison, soon after his invention of the carbon button transmitter, caused an electromagnet to act upon the iron diaphragm, and thus turned it into a relay, but it was not a success. Hughes (Proceedings of the Royal Society, vol. xxvii., p. 362, 1878), in his paper before the Royal Society in 1878, describing his extremely delicate microphones, stated that a telephone receiver, if included in the microphone circuit and placed upon the resonant board, caused a continuous sound to be produced. It follows, he said, that the question of providing a relay for the human voice in telephony is thus solved. Unfortunately, it was not solved; he had shown how to make a relay that would magnify a noise or musical note, but not one that would intensify articulate speech.