Stock Photo - TELEGRAPHONE: magnetic recording tele phone invented by Valdemar Poulsen (1869-1942). He applied for a patent on 1 December 1898; and the instrument aroused great interest at the Paris Exposition of 1900. RIBBON TELEGRAPHONE: Diagrams of the wire telegraphone which could record magnetically for one minute using piano wire.

Stock Photo: TELEGRAPHONE: magnetic recording tele phone invented by Valdemar Poulsen (1869-1942). He applied for a patent on 1 December 1898; and the instrument aroused.

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