The Reis telephone, was an invention by Philipp Reis inspired by a French article in 1854 (by Bourseul) on how to create microphone-like devices. His first successful work was achieved in October 1861. In 1862, Reis demonstrated his telephone to Wilhelm von Legat, Inspector of the Royal Prussian Telegraph Corps who produced an account of this (Legat, 1862), a translation of which came to Thomas Edison in 1875 and was used in Edison's successful development of the carbon microphone. (The Legat account includes drawings that are different from the one below suggesting that it is of a later version.) Edison acknowledged his debt to Reis:

The first inventor of a telephone was Phillip [sic] Reis of Germany only musical not articulating. The first person to publicly exhibit a telephone for transmission of articulate speech was A. G. Bell. The first practical commercial telephone for transmission of articulate speech was invented by myself. Telephones used throughout the world are mine and Bell's. Mine is used for transmitting . Bell's is used for receiving. (Edison 2006, [LB020312 TAEM 83:170])

Loudspeaker

Reis's speaker worked by magnetostriction. In his first receiver he wound a coil of wire around an iron knitting needle and rested the needle against the "F" hole of a violin. As current passed through the needle, the iron shrank and a click was formed. The image shown below is a more advanced version where the iron bar is clamped to a cigar-box-shaped resonator. This receiver is very insensitive. It produces weak sound but has good fidelity. It requires very high current and is a current-sensitive device rather than a voltage-sensitive device.

Reis was marginally successful. This instrument could transmit continuous musical tones but produced indistinct speech.