Pantelegraph

The Pantelegraph is a historic, electromechanical fax machine, which was invented by Giovanni Caselli and in 1855 patented by him. The Pantelegraph served to line by line receiving and row-wise transmission of video information over then usual Telegrafieleitungen and used for imaging electrochemical methods. In the United States Caselli received on June 29, 1858 a patent on his invention.

Operation

The sender of an image formed from this first electrically conductive metal on a film having an electrically non- conductive dye (ink). This template was clamped into the transmitter unit and scanned line by line by a thin metallic needle with about three lines per millimeter by a rocking motion. In areas where no ink has been applied, while the transmission-side is short-circuited and the battery voltage is low. The needle is in areas where the electrically non-conductive ink of the image original to prevent a short circuit, the higher voltage of the battery is the result. The so- induced template -dependent electrical voltages can be transmitted to the receiving unit far beyond a simple telegraph line up to some 100 km.

The working as a receiver Pantelegraph used a paper which is impregnated with a yellowish cyanide solution. About this paper line by line and sync out to the transmitter of a metallic needle, being triggered a chemical reaction in the cyanide solution by the different high voltages on the part of the sender: When current flows through the needle, the originally yellow cyanide compound turns into a dark blue hue.

For a correct figure, it is essential that the needles on the transmitter and receiver move as uniformly and synchronously. This is accomplished by an about 2 m to 3 m major pendulum having a weight of 8 kg, which is electromechanically initiated by two electromagnets.

The return of the needle through the oscillating movement required the same amount of time as the trace. This time was used in some pantelegraph for the transfer of a second template.

Applications

Around 1860 and in subsequent years the Pantelegraph especially in France was used for fluid transmission and verification of signatures in banking transactions. He was operated for this purpose, especially in post or rail stations, as well as the necessary connection to telegraph lines was possible there. The Pantelegraph was also of Napoleon III. uses.

Today there are only a few existing original pantelegraph, including the Musée des Arts et Métiers in Paris. 1961, the centenary of the pantelegraph, a connection from Paris to Marseille was made with these devices.