On January 19, 1878, Thomas Edison patented speaking telegraph (or telephone) in Italy.
Although Bell invented telephone first, Edison’s invention of the carbon-button transmitter proved to be a necessary component of successful telephone communication. To this day the carbon-button transmitter is used in telephone speakers and microphones.
Publication number: US474230 A
Patent Title: Speaking-telepgraph
Publication type: Grant
Publication date: 3 May 1892
Filing date: 27 Apr 1877
Priority date: 27 Apr 1877
Inventors: Thomas A Edison
Original Assignee: Thomas A Edison