Telephone Assembling Plant

Abstract

Man first used the postal service in conveying an intention or information, and then contrived the electric communication. However, the cable needed subsequent translations on both sides and also entailed difficulties in its use due to limits in contents of communication and other defects. Accordingly, it was necessary to convert the human voice into an electric signal, directly transmit it and talk each other by changing the electric signal back to the voice on the part of a recipient. Such a means of long distance conversations was invented by A.G. Bell in 1870.