Pantelegraph

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The pantelegraph was developed by Giovanni Caselli. It is a system of sending and receiving images over long distances by means of telegraph wiring. This system was actually the first prototype of a fax machine. The images transmitted by telegraph were reproduced using electrochemistry rather that optical image scanning. Special ferrous ink was used on an electroplated original "document" and transmitted over telegraph wires. Most common use of the pantelegraph was for signature verification for banking transactions and were found at railroad stations since this is where typically electric lines were used for telegram transmission. Later, these simple two-wire electric lines were the foundation for telephony.

The pantelegraph was a 3 meter tall pendulum-based system which from the point-of-origin "read" the plated document with a stylus on each swing, and would need to be in synchronization with its corresponding receiving station. This synchronization was achieved by using a simple electrical pulse or "heartbeat" that was adjusted by electromagnets at either side of the pendulum's swing.

There are few remaining examples of the original pantelegraph. A formidable display of the pantelegraph was in 1961 at the Musée National des Techniques, when a centennial celebration of the device was performed between Paris and Marseille. Again in 1982 their reliability was displayed; Two pantelegraphs were used for six hours a day, for several months, performing without error.

It is notable that the device was used by Napoleon III, and sent over 5000 images in 1870. The use of the pantelegraph was de-commisioned by the French government later that same year.