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Device 32620   Stimme
Speech/morse generator

Gerät 32620 (Device 32620) was a digital speech generator, developed in the early 1980s by the Institut für Kosmosforschung 1 (Space Research Institute) in the former DDR (East-Germany) and manufactured at the ZWG in Berlin. It was the successor to an analogue tape-based device known as Schnatterinchen and was used by the East-German Ministerium für Staatssicherheit (MfS), also known as the Stasi, for sending secret coded messages to its agents anywhere in the world, via the mysterious numbers stations that used to be operated on the short wave (SW) radio bands. The device is known by different names, including Eiserne Frau (iron lady) and Stimme (Voice).

Device 32620 measures 290 x 260 x 135 mm and weights approx. 7.1 kg. It has a sloped front panel with a 25-button keypad, an 8-position alphanumeric LED display and a 5-level paper tape reader. Messages can be entered manually on the keypad, via the serial port (by modem), or by means of a pre-recorded paper tape (telex).

Once a message is stored in the internal memory it can be played out either in morse code or as a spoken message, using a digitized female voice. When the device is switched off, the messages are retained by an internal NiCd backup battery.
  
Device 32620 (Stimme) ready for use

Device 32620 was developed in the early 1980s, to replace the ageing analogue tape-based Schnatterinchen (cacklerina) devices. The first protypes were tested by the Stasi in 1983, and in 1984 it was taken into production. It was used by Stasi (MfS) department HV A (Hauptverwaltung Aufklärung), for passing messages — generally encrypted with the unbreakable One-Time Pad — to its agents operating in Western countries. It was also used by the intelligence services of other Warsaw Pact countries, including the Soviet Union (USSR) and Poland, and countries like Cuba.

For speech digitizing and duplication of the speech module, Device 32621 — Programmierhilfe für Gerat 32620 (Programming aid for Device 32620) — was available separately. It is currently unknown how many 32620 device were made, but it is likely that the initial production batch in 1984 comprised ~ 50 devices, and that at least two batches of ~ 50 units each were made later. The device featured here, is a model 32620.2 with serial number 8704. It was manufactured in February 1987. In 1989, 6 more units were ordered for the HV A (8/A) and 27 for the IZSU, of which 15 were to be delivered in January 1990 and the remaining 12 in December 1990 [3]. 2

 Hear what the voice sounded like

  1. Part of the Akademie der Wissenschaften der DDR (East-German Science Academy).
  2. In November 1989 the Berlin Wall fell, so it is unclear whether these 27 units were delivered.

Device 32620 (Stimme) ready for use
32620 seen from the front left
Front vew
Rear view
Rear side
Rear panel wit open lid (for speech module)
Open lid (note the model and serial number on the inside of the lid)
Tape reader
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Device 32620 (Stimme) ready for use
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32620 seen from the front left
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Front vew
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Rear view
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Rear side
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Rear panel wit open lid (for speech module)
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Open lid (note the model and serial number on the inside of the lid)
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Tape reader

Features
The images below provide a quick overview of the features of the 32620. All controls are at the front of the device. At the bottom left is the mains power switch. Above it is a sloped panel with a 25-button keypad for user input. Above the keypad is an 8-position LED matrix display on which the current state of the device is shown. To the left of the keypad is a 5-level paper tape reader.

Click to see more

At the top left is the volume control knob for the internal speaker that is used for monitoring the output of the device. To its right is a switch to enable the line output (located at the rear). A LED shows whether or not the line output is currently enabled. To the left of the display are 3 further LEDs that show the mode (SPEECH or MORSE) and whether the STANDARD configuration is used.

Click to see more

All connections are at the rear of the device. There is a fixed power lead for connection to the 110, 127 or 220V mains AC network. In addition, the device can be powered by an external 12V DC source, such as the battery of a car. The audio line output is available on a KS-51 socket. It must be enabled with the LINE switch at the front panel and can optionally be terminated at 600Ω with a switch aside the socket. There is a built-in speaker, but it is also possible to connected an external speaker. Depending on the orientation of the plug, the internal speaker can be disabled.

At the bottom edge is a 6-pin military socket that carries the serial communication lines. They are connected to the SIO (USART) on the CPU board and allow synchronous or asynchronous serial communication. It is currently unknown whether this feature was supported by the firmware. 1 At the centre is a grey 26-pin EFS-26 socket on which several I/O lines are available. It allows the device to control external equipment – e.g. a transmitter – and to be remote controlled itself by external events. At the left is the hinged lid behind which the speech module must be installed.

 Operating instructions

  1. In the manual [A] this feature is listed as in Vorbereitung (in preparation).

Setup
The diagram below shows how the 32620 was used. In most cases it was placed close to the actual (high-power) short wave transmitter (TX), or at least in the same building, such that the 600Ω line output of the 32620 could be connected directly to the input of the transmitter. The line output carries the audio signal (speech or morse). In case morse code was used (rather than speech), a switched contact from the relay board was commonly connected to the transmitter.


Although a coded message could be entered on the device's keypad, it was usually delivered by courier (or telex) on 5-level punched paper tape, and loaded into the device via the tape reader at the front panel. Alternatively, the message could be sent directly from the Spy Centre via a (secure) telephone or data line, using a modem that was connected to the device's serial port.


Audio samples
Below are the contents of the German and Spanish speech modules. Click them to discover what the voice sounded like. The 4th audio file is a real broadcast from a Russian station (in German) that was recorded as late as 2019 by Karsten Hansky [8]. Click here for more real broadcasts.

 More examples of real broadcasts

HELP PLEASE — At present, German and Spanish are the only languages of which we have the original EPROM contents. These are the only two languages that were recorded with the same female voice at Funkobject Kasselberg in the DDR. All other languages (e.g. Polish, English and Russian) were recorded by the country which operated the device, using the 32621 programming aid. We would very much like to add other languages to our list. If you can provide the EPROM contents for such languages, please contact us.
Female voice
From 1961 onwards, the woman 1 shown in the image below, was one of the female speakers of the East-German numbers stations. Like most of the speakers, she was living with her family on the compound of Funkobject 2 Kesselberg. Initially the numerical messages were read live in one of the small studios in the basement of the Kesselberg site, where they were recorded on tape.

The tapes were then played back at specific times via a strong short wave (SW) transmitter with an output power between 10 and 100 kW.

In 1963/1964, whilst she was was on leave to give birth to a child, she was asked to lend her voice to the new Schnatterinchen device, that had just been developed. In the small studio in the basement, each word had to be fitted onto a piece of audio tape that was just 12-15 cm long.

According to her own account [4], the words Achtung (Attention) and Sieben (Seven) were the most difficult to record. Furthermore, the words had to be pronounced in such a way that they could be discriminated unambiguously through a noisy narrowband short wave radio channel. The pre-recorded tape segments were later mounted onto the discs of the Schnatterinchen device.

Some time later she was also asked to lend here voice to the Spanish version of the machine, which was subsequently recorded in the studio of the DDR broadcasting service 3 in Berlin. In the early 1980s, the same voice was digitized for use in the digital Device 32620 featured here.
  

For the lady in the picture, this meant the end of an era, but in the following years, she frequently tuned in to the Stasi frequencies on the short wave radio band, to confirm that here voice was still being used. In January 2010, she wrote a letter in which she explained here role as the voice [4].

 Read the full letter

  1. The name of the female speaker is currently unknown.
  2. Literally translated 'Radio Object' - here used to identify a site.
  3. Rundfunkhaus der DDR, Nalepastraße, Berlin (East Germany).

Speech samples
Below is an overview of the sound samples for the German language, along with their associated keys and morse code equivalents. Note the distinct – non-standard – pronunciation.  Play all
Key Morse German Pronunciation Description #
0 - Nul Nul Zero 1
1 .---- Eins Eins One 2
2 ..--- Zwei Zwo Two 3
3 ...-- Drei Drei Three 4
4 ....- Vier Vier Four 5
5 ..... Funf Fun-nuf Five 6
6 -.... Sechs Sechs Six 7
7 --... Sieben Sie-ben Seven 8
8 ---.. Acht Acht Eight 9
9 ----. Neun Neu-en Nine 10
: ...- Achtung Achtung Attention (start) 11
/ ........ Trennung Trennunk Separation (space) 1 12
+ ...-.- Ende Ende End (stop, end of transmission) 2 13
 Operating instructions


  1. According to the operating instructions [A], the morse code for the / sign is (
    -..-.
    ), but this is incorrect. In reality, the code (
    .........
    ) is played indefinitely, and should be avoided when sending a message in morse code.
  2. According to the operating instructions [A], the morse code for the + sign is (
    .-.-.
    ), but this is incorrect. The code that is played when the + key is pressed is (
    ...-.-
    ), which means SK (Silent Key).

Predecessor   Schnatterinchen
Device 32620 was the successor to an analogue machine known as Schnatterinchen (Cacklerina), that was developed in 1964/1965. It used short pieces of audio tape – fitted onto circular discs – as the storage medium.

 More information
  
Drum with 13 discs

Video footage
Quite a bit of footage that shows the 32620 in action, can be found on YouTube, most of which was published by Peter Staal in The Netherlands [6] and were recorded at the home of German collector Detlev Vreisleben in 2010 [2]. They show one or more machines in action and demonstrate how to alter the language. Below are some examples.

Various demonstrations of a 32620 device on YouTube



Block diagram
Below is the block diagram of the 32620. The device consists of a rack with plug-in cards, a power supply unit (PSU) and several PCBs that are fitted behind the front panel. The PSU is not shown in the diagram. At the heart of the system is the CPU board (DBZ-80-1), which is built around a Zilog Z-80 microprocessor, 1 two parallel I/O expanders (PIO) and one serial port (SIO).

The PIOs are used for interfacing to the keypad and the display. The SIO, also known as a USART, is for (a)synchronous serial communication with the outside world. It allows data to be sent to the device via a telephone modem. Also present on the CPU board, is the EPROM 2 that contains the firmware, and two SRAMs of 4kB each. The CPU runs at 2.458 MHz (crystal frequency 9.832 MHz).


An additional board (DBE) provides two additional PIOs that are used for interfacing the relay board, the audio board and the tape reader (at the front panel). On version 1 of the device, this board also contains a second 2716 or 2732 EPROM. On version 2 of the device (32620.2), this EPROM is omitted, whilst a double-size 2764 EPROM (8kB) is fitted on the CPU board.

The audio board contains the digital-to-analog (D/A) converter and the audio amplifier. It provides a signal to the built-in speaker, plus a line-level output for the radio transmitter. The relay board provides a number of galvanically separated (isolated) contacts that can be used to control external equipment. It also has a number of inputs that allow the device to be triggered by external events. The relay board also contains a NiCd backup battery for the CMOS SRAM.

The speech data (i.e. the sound samples) is held in the separate speech module, which should be intalled behind the hinged lid at the rear of the device. The speech module consists of one or two PCBs (speech cards), each of which holds six 2764 (8kB) EPROMs and additional logic circuits.

  1. Or the Eastern Bloc variant UB880.  Wikipedia
  2. Type 2716 (2kB) or 2732 (4kB). Version 2 of the CPU board has a 2764 (8kB) EPROM.



Click to see more

Interior
The device consists of two building blocks: the system unit, which consists of a backplane with a number of plug-in cards and the mains power supply unit (PSU), and a sloped front panel, behind which the remaining printed circuit boards (PCBs) are hidden. The interior can be accessed by removing four screws from the rear panel and two screws from the top, after which the top, rear and side panels can be removed. The front panel is held in place by four screws at the corners.

CPU board   DBZ
The CPU board is the heart of the device. It is built around a UB880 microprocessor made by MME – an unlicenced clone of the Zilog Z-80 [9]. It runs at 2.458 MHz and is complemented by a SIO and two PIOs. The latter are the interface to the keyboard and the display at the front panel.

This board also contains the two SRAMs (i.e. the message buffer) and the EPROM with the system firmware. Note that on version 2 of the board (shown in the image on the right), the EPROM is twice as large as on version 1, whilst the EPROM of the adjacent expansion board is omitted.
  
CPU board

As the 58-pin EFS58 AB backplane connector does not have enough pins to bring out all the I/O lines from the two PIOs, an extra EFS58 AB socket is provided at the rear end of the board.

This socket is fitted with an EFS58 plug that is wired to the front panel, as shown in the image on the right. The wire bundle is long enough to allow an extension board to be fitted between the CPU card and the backplane (for repair).

The expansion card (to the left of the CPU card), it fitted with a similar plug and wire bundle.

  
Female EFS58 AB socket at the rear end of the CPU card

Expansion board   DBE
The interfacing capabilities of the Z-80 platform are further enhanced with the expansion board shown in the image on the right. It holds two additional PIOs that are used to drive the audio board, the relay board and the tape reader. It also holds the select lines for the speech cards.

On version 1 of the device (32620), this board also holds a second EPROM. This EPROM is missing from the expansion board in version 2 devices (32620.2). At the rear end of the card is an additional EFS58 AB socket on which the I/O lines from the PIOs are brought out.

  
IO board

Audio board
The audio board holds the digital-to-analog (D/A) converter and the audio amplifier. It drives the built-in loudspeaker (embedded in the rear panel) and also provides the (600Ω) line output for connection to a short-wave (SW) transmitter.

At the centre of the edge of the board is the 600Ω output transformer. The output level can be adjusted with the recessed potentiometer.

  
Audio board

Relay board
The relay board provides a galvanically separcated interface to the outside world. It has a number of isolated relay contacts that can be used to drive external equipment. In addition, the board can receive external triggers for starting a message.

This board als holds a rechargeable 2.4V NiCd battery (two stacked 1.2V cells) that is used to retain the contents of the CMOS SRAMs (i.e. the message buffer) when the device is switched off. The battery is housed inside the orange cylinder.

  
Relay board with backup battery

Speech module
The sound samples for a particular language are held in a removable speech module that must be installed behind the hinged lid at the rear of the device. The speech module contains one or two PCBs, each of which holds six 2764 EPROMs of 8kB each, in which the spoken words are stored.

As this module was missing from the device in our collection, we have reverse-engineered it and have created the working reproduction shown in the image on the right.

 Reproduction speech module

  
Reconstructed speech cartridge. Click for full description.

Front panel
The remaining peripherals — the keyboard, the display, the tape reader and a couple of LED indicators — are fitted behind the sloped front panel. The front panel is electrically connected to the system unit by means of a wide EFS-58 male connector and a small 3-pin connector.

The image on the right shows the rear side of the front panel. The large PCB is the keypad. At the top left is a stack of three PCBs that are fitted to the rear of the display. They hold the character generator and the display driver. At the right is the tape reader.

  
Front panel - rear side

Power supply unit
The rightmost plug-in board (seen from the rear) is the Power Supply Unit (PSU). It is also the largest plug-in unit and is connected to the backplace by means of a combi-connector.

The mains power transformer is part of the PSU module. The image on the right shows the PSU with the printed circuit board (PCB) temporarily dismounted. It holds quite a few electrolytic capacitors which should be replaced by modern alternatives as part of a restoration.
  
PSU with dismounted PCB

Case without cover
Interior
Interior - rear view
Speaker and sockets mounted in the rear panel
Device 32620 with removed front panel
Backplane wiring
Backplane
Interior
CPU board
CPU board (component side)
CPU board (solder side)
CPU board with 8K EPROM (version 2)
ICs hidden under the SRAMs and EPROM
CPU board modifications
Female EFS58 AB socket at the rear end of the CPU card
IO board
IO board (component side)
IO board (solder side)
Audio board
Audio board
Audio board (component side)
Audio board (solder side)
Relay board with backup battery
Relay board with backup battery (restored)
Relay board with backup battery (component side)
Relay board with backup battery (solder side)
Front panel detached
Front panel - rear side
Front panel sub-PCB
Character generator board
Character generator board
Tape reader seen from the inside of the device
Power Supply Module (PSU)
PSU - solder side
Backplane connector
Side view
PSU with dismounted PCB
PSU board with many electrolytic capacitors
Crypto Museum speech cartridge
Crypto Museum speech cartridge
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Speaker and sockets mounted in the rear panel
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Device 32620 with removed front panel
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Backplane wiring
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CPU board (solder side)
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CPU board with 8K EPROM (version 2)
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ICs hidden under the SRAMs and EPROM
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CPU board modifications
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Female EFS58 AB socket at the rear end of the CPU card
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IO board
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IO board (solder side)
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Audio board
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Audio board (solder side)
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Relay board with backup battery
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Relay board with backup battery (restored)
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Front panel - rear side
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Front panel sub-PCB
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Character generator board
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Character generator board
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Tape reader seen from the inside of the device
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Power Supply Module (PSU)
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PSU - solder side
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Backplane connector
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PSU with dismounted PCB
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PSU board with many electrolytic capacitors
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Crypto Museum speech cartridge
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Crypto Museum speech cartridge

Restoration
When we obtained our 32620 device in 2017 [1], it was in an unknown state. The device had previously been working, but the speech module had gone missing and could not be retrieved. After switching the device ON, the display showed ERROR 15, indicating that the speech module was indeed missing. Pressing the STA/STP button, produced random characters on the display.

In addition, the second row of pixels of the LED display was dead, as shown in the image on the right. It was decided to address this problem first, as it did not require the presence of a speech module. The most likely candidate for the cause of the problem, was the display driver.   
Second row of pixels missing

After studying the circuit diagram [C], it was confirmed that the cause had to be found either on the character generator board (1.12) in the circuit around D3 and VT2, or on the display board (1.11) in the circuit around VT2. It turned out that the 22K resistor R10 (between D3 and VT2) on the character generator board had a crack. After replacing it, the display was complete again.

The next problem to address was the random nature of the display contents after pressing the STA/STP button. All plug-in cards were removed and inspected physically. It turned out that the backup battery for the SRAMs had been leaking and had caused damage to the relay board.

The NiCd cells were removed from the orange cylinder on the relay board and were replaced by a 1.5F/5V supercap. 1 The tracks at the bottom of the PCB were cleaned and restored, and the cylinder was refitted. In addition, the wiring between the battery and the PCB was replaced.
  
Corroded tracks (caused by leaking backup battery)

It was now possible to clear the contents of the SRAMs, by pressing (CLR) followed by (EX). It was also possible to set the mode to MORSE, turn on the KEYBOARD MONITOR and enter a message manually on the keypad. After entering random digits, the message was terminated with the (+) key, after which the display showed READY. Pressing (STA/STP) now played back the message.

As some of the buttons on the keypad were unresponsive, several of them were desoldered from the keypad PCB and taken apart, so that their interior could be cleaned thoroughly.

Inside each button is gold-plated contact strip on which a spring-loaded pad of conducting rubber is pushed down. Both the contact strip and the rubber pad were cleaned with alcohol and tested for conductivity before reassembling it and soldering it back in place on the keypad PCB. This part of the restoration has improved the overall reliability of the keypad considerably.
  
Removing a key cap

Another problem with equipment of this age is that most of the electrolytic capacitors will have lost their capacity by now. The Frolyt capacitors that are used in our 32620 are notorious for this, as are the capacitors from many other brands from the 1970s-1990s, also in the Western world.

As a precaution, it was decided to replace all electrolytic capacitors on all of the plug-in cards. When doing this, be especially careful with the CPU board. It is very sensitive to electrostatic discharge and the solder pads are very close to the adjacent tracks. As there is no solder mask, a barely visible short circuit is easily created. We also added 100 nF capacitors to the digital ICs. 2

This repair also cured the problem of a 'frozen' device after several hours of use. It was caused by a degraded capacitor in the reset circuit, that would short out after the device had warmed up.
  
Replaced capacitors. Note how close the tracks are to the solder pads.

The next problem to address was the tape reader at the front left of the device. Although it was in a cosmetically good condition, it didn't run when the the tape-feed button was pressed. A closer inspection told us that the motor wanted to run – it was running hot – but was somehow blocked.

After removing the tape reader from the front panel, it became clear that the ball bearings at both sides of the rubber pressure roller – which resides under the paper path – were rusty and were binding. It appears that the device had caught some water drops at some point in its life, which had not been treated appropriately.

The motor was temporarily removed, after which the ball bearings were treated with a derusting agent, penetrating oil, a quick drying cleaner and alcohol. Finally, the bearings were regreased and the small motor was mounted back in place.
  
Tape reader seen from the front left

After refitting the tape reader to the front panel, the unit was tested. Pressing the tape-feed button turns the motor on and feeds the paper at high speed. In addition, a message could be loaded by installing a tape, pressing the INP(UT) button and answering 'Y' to the question TR?.

At this point, the only remaining problem was the reconstruction of the sound module. This required the development of a printed circuit board (PCB) that could hold one or more EPROMs with the sound samples for a specific language.

Although a single board is sufficient for German, other languages, such as Spanish, may require an extra card to be used. As modern EPROMs are generally larger than the old 2764 devices used on the original speech card, we decided to use a single 27C020 on each card, so that we could store up to four languages in a single module.
  
Crypto Museum speech cartridge

An extra difficulty was the fact that the backplane requires the use of a specific 58-pin connector that was only made in the former DDR and a metal frame that was used in early DDR computers. Luckily, there were some very kind people on the Robotron Forum who were able to help us out. Our 32620 is now fully operational again and can play out messages in 4 languages plus morse.

 Description of the reproduction speech module

  1. A supercap is a good alternative for a rechargeable NiCd battery, especially in low-current applications like powering CMOS SRAM chips. The supercap used here, has a capacity of 1.5 Farad, which is sufficient for retaining a message for at least several weeks. Unlike batteries, supercaps do not leak.
  2. When designing digital circuits, it is good practice to connect a 100nF decoupling capacitor from the +V to ground, as close to the IC as possible. In the early days of digital design, these 100nF capacitors were often omitted, as a result of which circuits could become unstable and unreliable.

Problems
  • Error 15 (speech module missing)
  • Second row of pixels missing from display
  • Device 'freezes' after several hours of use
  • Arrow symbols missing from next/previous buttons
  • Backup battery worn out and leaking
  • Electrolytic capacitors worn out
  • Unresponsive keys on keypad
  • Tape reader motor not working (running hot)
Fixed
  • Broken EFS-58 connector at rear end of expansion board repaired.
  • 2nd pixel row of display fixed: R10 (22k) on board _1.12 replaced.
  • Arrow symbols added to next/previous buttons.
  • Backup battery swapped for 1.5F/10V supercap.
  • Electrolytic capacitor swapped on Relay board.
  • All electrolytic capacitors swapped on CPU board.
  • All electrolytic capacitors swapped in PSU.
  • 6 buttons of the keypad removed, disassembled, cleaned and refitted.
  • Tape reader repaired and greased.
  • Output cable KS-51 — XLR added.
  • Speech cartridge reconstructed.
Second row of pixels missing
Second row of pixels missing
Character generator board
Corroded tracks (caused by leaking backup battery)
Relay board with backup battery (restored solder side)
Relay board with backup battery (restored)
Removing a key cap
Replaced capacitors. Note how close the tracks are to the solder pads.
Tape reader
Inside the tape reader
Tape reader seen from the inside of the device
Tape reader seen from the front left
Tape reader seen from the front right
Tape reader seen from the front
Tape reader seen from the rear right
Tape reader seen from the top
Audio line cable
Crypto Museum speech cartridge
Crypto Museum speech cartridge
Crypto Museum speech cartridge
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Second row of pixels missing
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Second row of pixels missing
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Character generator board
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Corroded tracks (caused by leaking backup battery)
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Relay board with backup battery (restored solder side)
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Relay board with backup battery (restored)
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Removing a key cap
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Replaced capacitors. Note how close the tracks are to the solder pads.
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Tape reader
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Inside the tape reader
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Tape reader seen from the inside of the device
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Tape reader seen from the front left
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Tape reader seen from the front right
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Tape reader seen from the front
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Tape reader seen from the rear right
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Tape reader seen from the top
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Audio line cable
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Crypto Museum speech cartridge
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Crypto Museum speech cartridge
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Crypto Museum speech cartridge

Connections
All connections of the 32620 are located at the rear panel. There are sockets for connection of an external speaker, transmission line (Leitung) and serial port (RS232). There is also an expansion socket (Bu1) for driving external equipment and for responding to external events. Below is the pinout of the sockets, as seen when looking into the sockets from the rear of the device.

LINE output
The line output of the device is available on a 5-pin screw socket at the rear of the device. This socket is similar (but not identical) to a 5-pin DIN socket. It accepts RFT plug KS 51 with external thread (type 063-01:00), a.k.a. TGL 31428. Below is the pinout when looking into the socket.

  1. Line out (A)
  2. unused
  3. Line out (B)
  4. unused
  5. unused
DATA input
Also at the rear is a 6-pin military socket on which a serial port is available. The port is driven by the SIO on the CPU board, and can be synchronous as well as asynchronous. In the latter case, no hardware handshaking is used. Below is the pinout when looking into the socket.

  1. Clock
  2. TX Data
  3. unused
  4. GND (0V)
  5. unused
  6. RX Data
External switchboard   Bu 1
At the rear is a 26-pin socket for controlling external equipment and for driving the 32620 from external events. The socket is an EFS26 AB female part. The upper nine rows (1-9) are connected to the isolated contacts of three internal relays (rs 1, 2, 3). The lower four rows (10-13) are for the external inputs. Below is the layout when looking into the socket from the rear of the device.

  1. A: rs 2/2 n.o. 4
    B: rs 2/1 n.c. 4
  2. A: rs 2/2 n.c. 4
    B: rs 2/1 n.o. 4
  3. A: rs 2/1 common 4
    B: rs 2/2 common 4
  4. A: rs 1 n.o 3
    B: rs 3/1 common 4
  5. A: rs 1 common 3
    B: rs 3/2 n.o. 5
  6. A: unused
    B: rs 3/2 n.c. 5
  7. A: unused
    B: rs 3/1 n.c. 5
  8. A: unused
    B: rs 3/1 n.o. 5
  9. A: unused
    B: rs 3/2 n.o. 5
  10. A: Remote 1
    B: GND
  11. A: Latched 2
    B: GND
  12. A: STA/STP1
    B: STA/STP2
  13. A: OUT1
    B: OUT2

    n.o. = normally open, n.c. = normally closed
  1. Remote start/stop input (active high).
  2. When connected to GND (active low).
  3. RS1 = Morse output.
  4. RS2 = Running.
  5. RS3 = END.

Specifications
  • Type
    Speech/morse generator
  • Purpose
    Transmission of coded messages in speech or morse
  • Memory
    3791 characters (including spaces)
  • Backup
    Internal 2.4V NiCd battery
  • Morse
    Tone or relay contact
  • Tone
    800, 1000 or 1200 Hz
  • Speech
    2 x 48kB (max. 13 words, 16 seconds)
  • Speed
    30 to 240 characters per minute (morse) in 10 steps
    70 - 110 words per minute (speech)
  • Pitch
    0%, -10%, +10%
  • Input
    5-level paper tape (ITA-2) (CCITT-2)
    Manual (via keybord)
    RS232 serial port (modem)
  • Output
    Audio 600Ω 0 - +6dB (adjustable)
    Relay contact (morse only)
    Internal speaker
    External speaker
  • Speaker
    500mW into 6Ω
  • Remote
    STA/STP, OUT
  • Serial
    Synchronous or asynchronous (RS232) serial port
  • Mains
    110, 127 or 220V AC (switchable), 22 Watt
  • Battery
    12V DC, 2A
  • Temperature
    +5 to +40°C
  • Storage
    0 to +55°C
  • Humidity
    90% (max.)
  • Dimensions
    290 x 260 x 135 mm
  • Weight
    7.1 kg
Nomenclature
Although the device was officially designated 2620 (later: 32620) (i.e. the Stasi project number) 1 it was known by its users under various names, the most common of which are listed below.

  • Gerät 2620
    Device 2620
  • Gerät 32620
    Device 32620
  • Sprach-Morse-Generator
    Speech-Morse-Generator
  • Stimme
    Voice
  • Eiserne Frau
    Iron lady
  • Kluge Frau
    Clever lady
  • Schlaue Frau
    Smart lady
  1. When the development of the device was initiated in the late 1970s, it was given the Stasi project number 2620. This number was later prefixed with a '3', which is the last digit of Stasi department Abteilung 33.
     More about Stasi project numbers
Known serial numbers
Below is an non-exhaustive list of model and serial numbers of 32620 devices that may help to determine how many units were manufactured. It is likely that the first two digits of the serial number represent the year of manufacturing. Please report any devices that are not listed here. The model, version and serial number are printed inside the hinged lid at the rear.  Contact us

  • 3 2620
    8401
    ?
    ?
  • 3 2620
    8402
    ?
    ?
  • 3 2620
    8409
    ?
    ?
  • 3 2620
    8410
    ?
    ?
  • 3 2620
    8414
    ?
    ?
  • 3 2620
    8415
    ?
    ?

  • 3 2620
    8501
    1985 Nov
    ?
  • 3 2620
    8515
    1985 Nov
    Spionagemuseum Berlin (Germany)

  • 3 2620.2
    8704
    1987 Feb
    Crypto Museum (Netherlands)
  • 3 2620.2
    8729
    1987 Feb
    ?
  • 3 2620.2
    8732
    1987 Feb
    ?
From this list is is clear that there were at least three production batches: in 1984, 1985 and 1987 respectively. It is also known that additional units were ordered in 1989. If each production batch consisted of 50 units, it is likely that between 150 and 200 units were manufactured.


EPROM contents
Please note that there are two versions of the device. The first version (32620) uses two system EPROMs: one on the CPU board and one on the expansion board. These are 2716 (2kB) or 2732 (4kB) types. Furthermore, the speech board has room for six 2764 EPROMs (8kB), which is sufficient for the German language, but not for Spanish, which required 8 such EPROMs.

The boards of the second version of the device (32620.2) are completely different. There is only one system EPROM, which is a 2764 (8kB). It is likely that it contains the contents of both the former system EPROMs (from the CPU board and the expansion board). Furthermore, the speech board has been enhanced to accomodate eight 2764 EPROMs, which is sufficient for Spanish.

Download
  1. Recreated by Crypto Museum from surviving recordings.

Datasheets
  1. EPROM 2764 (8kB)
    ST Microelectronics, 2000.

  2. µPD446 2048 x 8 bit static CMOS RAM
    NEC, December 1980.
Literature
  1. Detlev Vreisleben, Agentenfunk und die verwendeten Verschlüsselungsverfahren
    Radio Kurier - welweit hören, December 2011. pp. 26-31.
Documentation
  1. Gerat 32620 Sprach - Morsegenerator (German) 1
    Operating Instructions. Extracted from [C].
    MfS, 18 February 1985. 27 pages.

  2. Bedienungsanleitung Gerät 32620 1,2
    Operating instructions for Device 32620 (handwritten draft).
    March 1983. MfS-OTS Nr. 4060.

  3. Sprach-Morse-Generator und Programmiergerät 32620 / 32621 1
    Full description of Speech-Morse-Generator and Programming Aid (German).
    Nr. 1176-0.1 KB (4). February 1985. MfS-OTS Nr. 4061.
     More about Device 32621 (programming aid)
  1. Document from BStU archives [7], kindly supplied by Detlev Vreisleben [2].
  2. In the handwritten draft, the device is identified as 32026, which is clearly wrong and should be 32620.

References
  1. Anonymous, Device 32620.2 - THANKS !
    Crypto Museum, July 2017.

  2. Detlev Vreisleben, Personal correspondence
    July 2017 — January 2022.

  3. Operativ-Technische Sektor, Abteilung 33, Leistungsplan 1990 fuer die KST: 3360 2
    VVS B77-89, 14 October 1989. Pages 1 and 7.

  4. Anonymous, Letter from female East-German 'numbers speaker'
    30 January 2010.

  5. Bundesbeauftragte für die Stasi-Unterlagen (BStU) 1
    Federal Commissioner for the Stasi-Records.

  6. Peter Staal, YouTube channel
    Retrieved July 2017.

  7. Jorg Drobick, YouTube channel
    Retrieved July 2017.

  8. Karsten Hansky, Sound samples of current Numbers Stations
    Received August 2015 - September 2019. Many thanks!

  9. Wikipedia, U880
    Retrieved December 2021.
  1. Full name: Bundesbeauftragte für die Unterlagen des Staatssicherheitsdienstes der ehemaligen Deutschen Demokratischen Republik (DDR) — Federal Commissioner for the Records of the State Security Service of the former German Democratic Republic (GDR) — officially abbreviated to BStU.
  2. Document from BStU archives [5], kindly supplied by Detlev Vreisleben [2].

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Crypto Museum. Created: Wednesday 19 July 2017. Last changed: Friday, 18 February 2022 - 22:10 CET.
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