device for recording, storage (usually brief), and subsequent reproduction (usually by typewriter or word-processing system) of spoken messages. Dictating machines may be either mechanical or magnetic and may record the voice on wire, coated tape, or plastic disks or belts, which can be removed from the machine after dictation and forwarded to the point of transcription. The transcribing machine reproduces the dictated message in voice form. Early dictating machines were mechanical and, as in Thomas A. Edison's (Edison, Thomas Alva) original invention, phonographically recorded the sound waves of the human voice on a wax cylinder; a similar device played the record back for transcription. Later adaptations used plastic disks and belts, and upon the development of magnetic wire and then tape recording, loops of wire and magnetic disks and belts were used to record. Microelectronic and solid-state developments have made possible significant reductions in size of both the dictating and playback equipment and the disks or cassettes used. The playback device used by the transcribing typist usually is operated by foot controls.