Improvement in electrical-contact telephones : specifications forming part of Letter Patent no. 222,652 dated December, 1879, application filed August 11, 1879

Patent filed on August 11, 1879. Witnesses listed as Alex L. Hayes and A. H. Vinal.

Patent heading says: "Emile Berliner of Boston, Massachusetts."

Patent detailing Berliner's improvements to the design of the electrical contact telephone or microphone. With accompanying drawings.

telephone microphone electric apparatus and appliances patent emile berliner collection 1871 1965 series 11 patents 1879 1909 emile berliner collection 1871 1965 emile berliner and the birth of the recording industry motion picture broadcasting and recorded sound division emile berliner electrical contact telephones letter patent ultra high resolution high resolution

01/01/1879

Library of Congress

https://www.loc.gov/

Public Domain