Telephone (Transmitter and Receiver), Philipp Reis

Reis first reproduced single tones on a telephone. Speech could only be understood indistinctly.
Reis based the design of his transmitter on the human ear. The sounds go via the cone to a diaphragm which they set vibrating. This opens or closes a circuit. In the receiver the incoming signals cause the needle to vibrate. The wooden box serves as a resonator.