Spy sets
Burst encoders
Logo (click for homepage)
Speicher Burst Encoder
High-speed morse burst encoder - wanted item

The Speicher was a fully electronic burst encoder that could send numbers in morse code a very high speed. It was developed in the 1970s in Germany, probably by Pfitzner who had also developed part of the SP-20 spy radio set. Speicher was developed for the SP-20 and replaced earlier mechanical burst encoders, such as the NATO-issued RT-3 and the American AN/GRA-71. In the Netherlands, it was also used in combination with the earlier SP-15 spy radio set.
Speicher is the German word for Memory, which perfectly describes its function. The unit is housed in a grey case that is similar to the cases of the SP-20 spy radio set. It is powered by an internal battery that can be recharged by a built-in power supply unit directly from the mains.

At the right of the front panel are the sockets for the transmitter (key output) and the 110V or 220V AC mains. At the left is a recessed MODE selector and two push buttons, marked START and CALL. The MODE selector has four settings: OFF, REC, SBY (standby) and PLB (play-back).

At the top is a small recessed keypad with 12 buttons. Ten of these are for the numbers (0-9) and the two remaining ones are marked G and F. Just above the keypad is a small window with five red LEDs that are used for counting the number of characters in a five-letter group.

The Speicher was probably developed only for the (grey) stay-behind version of the SP-20 and was to be used instead of the earlier mechanical RT-3 burst encoder. It has not been found with the (green) military version of the SP-20. Evidence of the use of Speicher in combination with the SP-15 spy set was found in The Netherlands, where it turned up in the only known surviving SP-15 Stay-Behind container. This container is now in the collection of Museum Jan Corver [1].

In the early 1980s, the Speicher was replaced by the more versatile MMP burst encoder. It was capable of sending both letters and numbers in morse code at a variety of speeds, ranging from 15 baud to an impressive 1200 baud. Some Speicher encoders remained in service however.

When preparing a transmission, the text first had to be translated into numbers, as the Speicher is not capable of sending letters. The MODE selector was then placed in the record position (REC) and the START button was pressed to place the memory counter at the beginning (initialize).

The numbers are then entered in groups of five that are separated by a Group Space by pressing the (G) button. The five LEDs behind the window on top of the unit are used to count the number of characters in a group. When all five LEDs are lit, the G-button has to be pressed. This inserts a pause and clears the LEDs. Once the message is complete, the F-button is pressed (Finish).

The Speicher should now be connected to the transmitter by means of a special cable that is inserted into the green socket at the front right. The cable shown here was issued for the SP-15 spy radio set. The MODE selector should then be place in the play-back position (PLB) after which the START button is pressed. Once the burst transmission has finished, the transmitter should be turned off again and the MODE selector of the Speicher is set to OFF. This clears the memory.
Help required
At present we have no further information about the Speicher and its capabilities. If you know more about this device, or if you have documentation about it, please contact us. Crypto Museum is still looking for a Speicher for our collection.
  1. Museum Jan Corver, Complete SP-15 set in water-tight container
    Photographs taken during the exhibition Secret Messages.
    Crypto Museum, October 2008.

Further information

Any links shown in red are currently unavailable. If you like this website, why not make a donation?
Copyright 2009-2013, Paul Reuvers & Marc Simons. Last changed: Saturday, 21 June 2014 - 08:55 CET
Click for homepage