The Feldfernschreiber is a military, field version of the Hellschreiber, the teleprinter patented by Rudolf Hell in 1929. The purpose of the device is to transmit text messages over a wire or radio connection. Unlike earlier teleprinters, the Feldfernschreiber transmitted complete information about the appearance of the character and not its symbolic, codified representation. This made the transmission resistant to interference, as a distorted character generally still remained legible. This feature also allowed the device to be easily adapted to work with different alphabets and writing systems.
During World War II, devices based on Hell’s system were used by field units of the German army. After the war they were widely used by mail and press agencies. Much like standard teleprinters, the devices remained in use even until the 1990s. Presently, the Hell transmission system is still used by ham radio enthusiasts for amateur radio communication.
The Mende company was established in 1923 by Otto Hermann Mende and Rudolf Müller. Initially, it was mostly known for the production of radios under a license from Philips. The production profile gradually changed from the second half of the 1930s as a result of orders from the German army. Before and during World War II, the Mende factory mostly manufactured equipment for the Kriegsmarine and Luftwaffe.
The inventor of the Hellschreiber, Rudolf Hell, was one of the most prominent engineers and machine designers of the 20th century. Apart from the Hell system, he invented the electronically controlled Klischograph photo-engraving device (1951), the first fax machine (1956), the colour scanner (1963), and computerised CRT (1965). He is rightly referred to as the “Edison of the graphics industry” and the “father of digital text processing”.