The original idea

"Suppose that a man speaks near a movable disc sufficiently flexible to lose none of the vibrations of the voice; that this disc alternately makes and breaks the currents from a battery: you may have at a distance another disc which will simultaneously execute the same vibrations...It is certain that, in a more or less distant future, speech will be transmitted by electricity."
- M. Charles Bourseul, French telegraphist, 1854