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Enigma
M3
M4
  
Lesegerät   MZL
Enigma external lamp panel - wanted item

MZL, 1 or Fernlesegerät (read-out device), is an external lamp panel for the Naval Enigma cipher machine, 2 manufactured during World War II (WWII) by Konski & Krüger 3 in Berlin (Germany) for the German Navy (Kriegsmarine). It replaced the Enigma's existing lamp panel and was intended for situations in which the cipher clerk (commonly the radio operator) was not allowed to read the contents of a decrypted message, for example messages that were intended for the commanding officer only. The message was then entered by the clerk and read/written-down by the officer.

The device consists of two parts that are inter­connected by a fixed 130 cm long cable. The smaller part is a rectanglular connector with 26 contact pins, that can be installed in place of the existing lamps of a Naval Enigma. For this, the lightbulbs of the Enigma must be removed. It is held in place by four spring-loaded latches 4 that also act as the common electric contact.

The larger part is the read-out device. It has a sloped side with 26 lightbulbs, that is covered by a removable alphabet film with the letters A-Z, similar to the one on the Enigma machine itself.
  

The device is constructed in such a way that it can be placed at both sides of the Enigma — at the left or at the right — each of which requires the device to be configured accordingly. For this purpose, the connector contains an integrated slider and a window that shows the current setting (LINKS/RECHTS). Furthermore, the alphabet film that covers the lamps can be fitted upside down.

When placing the read-out device at the right side of the Enigma, the slide switch on the connector must be set to RECHTS (right) and the connector must be installed on the Enigma's lamp panel in such a way that the word RECHTS is readable. This configuration is shown on the right. The read-out device is placed with the word Rechts at the top and the lamp film is installed so that the letters A-Z are readable.

When used at the left side of the Enigma, the slide switch is set to LINKS before the connector is installed on the lamp panel of the Enigma.
  

In that case, the cable leaves the Enigma at the left side. In this configuration, the read-out device has to be turned upside-down – so that the word Links is at the top – and the alphabet film has to be turned around, so that the letters remain readable. Depending on the position of the slide switch, a metal bracket extends from the far end of the connector to avoid it being installed the wrong way around. In the wrong position it interferes with a mounting post inside the Enigma.

Many thanks to Glen Miranker for lending us his Lesegerät and allowing us to investigate it [1].

  1. The exact meaning of the MZL designator is currently unknown, but as the the letters 'MZ' were commonly used by the German Navy as a prefix for add-ons like the Schreibmax printer, it is possible that MZL was short for something like Marine Zusatzgerät Lampenfeld (Navy add-on lamp panel) or Marine Zusatz­gerät Lesegerät (Navy add-on read-out device).
  2. The device is suitable for the Enigma M1, M2, M3 and M4.
  3. During WWII, Konski & Krüger (K&K) — manfuacturer code gvx — was the main manufacturer of Enigma machines under licence from Heimsoeth und Rinke (H&R) — manufacturer code jla.
  4. One of the four latches is missing from the device shown here.

Lesegerät (MZL) complete
Plug configured for LEFT side use (LINKS)
Contact pins (bottom view of connector)
MZL configured for the left side of the Enigma
Lamp screen removed
Light bulbs
Hold-down bolts
Enigma with Lesegarät (MZL) installed at the left side of an Enigma M4
A
×
A
1 / 8
Lesegerät (MZL) complete
A
2 / 8
Plug configured for LEFT side use (LINKS)
A
3 / 8
Contact pins (bottom view of connector)
A
4 / 8
MZL configured for the left side of the Enigma
A
5 / 8
Lamp screen removed
A
6 / 8
Light bulbs
A
7 / 8
Hold-down bolts
A
8 / 8
Enigma with Lesegarät (MZL) installed at the left side of an Enigma M4

Features
The image below gives an overview of the various parts of the external lamp panel. At the top left is the actual read-out unit, which has a sloped lamp panel with 26 flat-faced lightbulbs. The lightbulbs are covered by a metal panel that holds the alphabet film. This panel can be installed in two ways: straight and upside down, depending on which side of the Enigma it will be placed. The read-out unit has rubber feet at the rear and at the bottom, so that it can be placed in two positions: with the text Rechts (right) visible at the top, or with the text Links (left) at the top.


At the bottom is the connector. It is permanently connected to the read-out unit by means of a 27-wire cable. At its top is a slide switch that allows the device to be configured for use at the left side (LINKS) or the right side (RECHTS) of the Enigma. The selected configuration is shown through six cut-out windows at the top of the connector. At the bottom of the connector are 26 rigid contact pins that mate with the empty lamp sockets of the Enigma. At the four corners are spring-loaded latches 1 that clamp the connector to the edges of the Enigma's lamp panel.

  1. Note that one of the four latches is missing from the device shown here.

Parts of the Lesegerät (MZL)
Plug configured for RIGHT side use (RECHTS)
Plug configured for LEFT side use (LINKS)
Contact pins (bottom view of connector)
Cable with strain relief
Spring-loaded latch
Spring-loaded latch
Disengaging a spring loaded latch
Slide switch LINKS/RECHTS
Metal bracket to avoid installing the connector the wrong way around
All lightbulbs removed from the lamp panel of the Enigma M4
Enigma M4 and MZL connector
26-pin connector of the MZL installed on an Enigma M4 - configured for use at the LEFT side
Connector installed on Enigma M4 - configured for RIGHT usage - top view
Rear view with manufacturer shield
Model and serial number
Enigma with Lesegarät (MZL) installed at the left side of an Enigma M4
Enigma with Lesegarät (MZL) installed at the RIGHT side of an Enigma M4
B
×
B
1 / 18
Parts of the Lesegerät (MZL)
B
2 / 18
Plug configured for RIGHT side use (RECHTS)
B
3 / 18
Plug configured for LEFT side use (LINKS)
B
4 / 18
Contact pins (bottom view of connector)
B
5 / 18
Cable with strain relief
B
6 / 18
Spring-loaded latch
B
7 / 18
Spring-loaded latch
B
8 / 18
Disengaging a spring loaded latch
B
9 / 18
Slide switch LINKS/RECHTS
B
10 / 18
Metal bracket to avoid installing the connector the wrong way around
B
11 / 18
All lightbulbs removed from the lamp panel of the Enigma M4
B
12 / 18
Enigma M4 and MZL connector
B
13 / 18
26-pin connector of the MZL installed on an Enigma M4 - configured for use at the LEFT side
B
14 / 18
Connector installed on Enigma M4 - configured for RIGHT usage - top view
B
15 / 18
Rear view with manufacturer shield
B
16 / 18
Model and serial number
B
17 / 18
Enigma with Lesegarät (MZL) installed at the left side of an Enigma M4
B
18 / 18
Enigma with Lesegarät (MZL) installed at the RIGHT side of an Enigma M4

Specifications
  • Device
    External lamp panel
  • Purpose
    Remote readout by officer
  • Brand
    Enigma
  • Model
    MZL
  • Year
    1941
  • Manufacturer
    Konski & Krüger (K&K) — manufacturer code 'gvx'
  • Customer
    German Navy (Kriegsmarine)
  • Compatibility
    Enigma M1, M2, M3, M4
  • Dimensions
    Connector 240 × 70 × 45 mm
    Read-out unit 258 × 90 × 100 mm
  • Weight
    1815 g
Nomenclature
  • MZL
  • Fernlesegerät
  • Lesegerät
  • Zusatzgerät Lampenfeld
  • Sichtgerät
References
  1. Glen Miranker, Lesegerät (MZL)
    Crypto Museum, October 2022.
Further information
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© Crypto Museum. Created: Tuesday 11 October 2022. Last changed: Saturday, 27 January 2024 - 09:19 CET.
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