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Die schreibende Enigma
Printing Enigma machine · 1924-1926

Die schreibende Enigma (English: the printing Enigma) was an electromechanical cipher machine, developed between 1924 and 1926 by Chiffriermaschinen AG (ChiMaAG) in Berlin-Wannsee (DE), as the successor to the so-called Handelsmaschine. It was the second machine to be sold under the Enigma brand and was succeeded in 1929 by the improved Enigma H or Enigma Model H29.

Unlike Die Handelsmaschine – which featured a rotating print wheel that was unreliable at high speeds – the Schreibende Enigma is equipped with regular type-bars, which were already used widely in the typewriters of the era. For this reason, the machine is also known under the name Typenhebelmaschine (type bar machine).

The rare photograph shown on the right shows the first version of the machine, which is based on a 'Cardinal' typewriter made by Uhrenfabrik vorm. L. Furtwängler Söhne in Furtwangen (DE). An additional mechanism is added at the right.
  
Top view of 'Die schreibende Enigma'. Photo courtesy FRA [1].

Development of the machine was started in late 1923, with a projected introduction sometime in 1924, but this appeared unrealistic due to manufacturing problems and reliability issues with respect to the printing mechanism. The nature of these problem is currently unknown, but it prompted manufactuer – ChiMaAG – to look for a different supplier of the printing mechanism.

CONFUSION — Over the years, the general understanding of the model names and designators of the various Enigma machines, has changed several times. For a long time, it was assumed that the machine described on this page — i.e. Die schreibende Enigma — was known as Enigma B, but from surviving documents it has meanwhile become clear that Enigma B was one of the first lamp-based Enigmas (Glühlampenmaschine) [2]. It seems likely that the first two printing Enigma machines did not have a single-letter type designator.
Improved version
Around 1925, a new supplier of the printing mechanism was found and development of the Schreibende Enigma continued. The new version was released around 1926. It is currently unknown who the new supplier was and how many machines were eventually produced, but it seems likely that a small number were manufactured in 1927, with another small batch in 1928.

The two images on the right were found in 2009 in the archives of the Swedish National Defence Radio Establishment (FRA) [1], and are believed to show the improved version of the machine.

Keyboard, type-bars, ink ribbon and carriage of an existing typewriter are used, whilst additional crypto-related parts were added at the right and behind a panel in the space under the printer.

The keyboard consists of 60 keys, divided over 6 rows, plus a space bar with a special SHIFT-key at either side. The SHIFT-key at the left is used to switch to figures, whilst the one at the right returns to letters. Pressing either SHIFT-key automatically inserts a space in the output.

As the cipher rotors had only 26 contacts, only the letters A-Z were included in the ciphertext. This means that a special trick had to be used to SHIFT between letters and figures, such as the one described in German patent DE425566.
  
Top view of 'Die schreibende Enigma'. Photo courtesy FRA [1].

In the patent, filed on 28 February 1924, inventor Paul Bernstein describes a system to use the letters 'J' and 'Q' for switching to numbers and back to letters. In the output, the real letter 'J' is replaced by an 'I' and the letter 'Q' is replaced by a 'K', so that the text is still comprehensible.

The image on the right shows the same version of the machine from the front right, whith the cipher compartment under the type-bars visible. When zooming in on this photograph it becomes clear that there are two scramblers, one at the left and one at the right, mounted on a common axle. Each of the scramblers consists of two cipher rotors held between entry and exit discs.

The rest of the cipher mechanism is housed in the large blob at the right side of the machine. It has several knobs for setting the initial position of the rotors and a set of smaller wheels at the top right, of which the current setting is visible through windows in the machine's metal cover.
  
Schreibende Enigma on supporting table, seen from the front. Photo courtesy FRA [1].

It is likely that these smaller wheels are used for setting the message key – consisting of 4 letters and 5 digits – using the knobs on the right. As an extra detail, this photograph shows two symbols at the front edge of the machine – under the keyboard – which might be the company logo of the new supplier of the printing mechanism. In 1929, the Schreibende Enigma was succeeded by the Enigma Model H29 (designator Ch.14) — the last printing Enigma machine.

Glow lamp machine
In the meantime, a smaller and much more affordable machine had been introduced in 1924. Known as the Glühlampenmaschine (glowlamp machine) it used light bulbs for its output and was easier to handle as it was a reciprocal system. The first machine of this type was the Enigma A, soon followed by Enigma B and Enigma C. It was the beginning of a long line of cipher machines that ended with the Enigma IM4, that were used by the German Armed Forces during WWII.

First version of the 'Schreibende Enigma'
Second version of the 'Schreibende Enigma' seen from the top right
Second version of the 'Schreibende Enigma' seen from the front right, with front cover removed.
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First version of the 'Schreibende Enigma'
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Second version of the 'Schreibende Enigma' seen from the top right
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Second version of the 'Schreibende Enigma' seen from the front right, with front cover removed.



References
  1. Försvarets Radioanstalt (FRA), Photographs of Die schreibende Enigma
    Swedish National Defence Radio Establishment. Received September 2009.
    Photographs reproduced here by kind permission of the FRA.

  2. Frode Weierud, Forthcoming Enigma History publication
    Personal correspondence. September 2009 — January 2019.
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Crypto Museum. Created: Sunday 13 September 2009. Last changed: Monday, 22 May 2023 - 14:52 CET.
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