In 1833, Carl Friedrich Gauss and Wilhelm Eduard Weber invented the world’s first electromagnetic telegraph.
An approximately 1.2 km long double wire line led from the induction-operated sign transmitter from the observatory to the Physical Cabinet, Weber’s workplace. Later, the line was extended by another 60 m to the Gauss House.
The receiver was a horizontally oscillating magnetic rod in a wire coil, the deflections of which were observed by means of a telescopic sight via a mirror rotating with the magnetic rod.
The deflection of the magnetic rod was described with right/left or plus/minus.
The table opposite was used for coding the characters.