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ATF Hellschreiber
DDR variant of the Hellschreiber

The Abtastfernschreiber or ATF (scanning teleprinter) was a field teleprinter, developed between 1952 and 1954 by RFT in the former East Germany (DDR) for the Kasernierte Volkspolizei (KVP) (Internal People's Police). It was also used by the Nationale Volksarmee (NVA), the People's Army of the DDR. The machine was clearly based on the Hellschreiber system developed by Rudolf Hell. ATF is also known as FFS-002-00001, as RFT ATF Schreiber and as Feldfernschreiber (FFS).
The original Hellschreiber principle was patented by Rudolf Hell in 1929, and many Hellschreiber and Feldhellschreiber machines were used by the German Army before and during WWII, both via landlines and over short-wave (SW) radio links.

Hellschreiber machines were manufactured in a number of German factories, including one in Berlin Dahlem that had opened in 1939 and another one in Berlin Teltow that had opened in 1940. Once the war was over, East-Germany was separated from West-Germany and the factories ended up at the Eastern Block side of the border.

Some of the Hell factories subsequently fell into East-German hands, along with spare parts and the 'know-how'. So, when the newly established People's Police (the Kasernierte Volkspolizei, or KVP) needed a field teleprinter in 1952, it was decided to use the acquired HELL-technology.
The FFS-002-00001 ready for use

The image above shows the final version of the machine that was designated FFS-002-00001. The letters 'FFS' are probably the abbreviation of Feldfernschreiber (field teleprinter) and the number '002' tells us that this was the second design. Globally speaking, the machine resembles the original Feldhellschreiber. It is housed in a sturdy transit case. The keyboard is located at the bottom with a printer to its left. The upper part of the case contains the line amplifier [2].

The basic design of th ATF Hellschreiber was created in 1952, but the first machines were not deployed until 1954/1955, when they entered service with the KVP (Police) and later, in 1956, with the NVA (Army). The FFS-002-00001 was part of Funkstation (radio station) FK 1a and is described on pages 82-87 of the DV-44/14 operator's manual [3]. The machines were phased out in the late 1950s and the early 1960s, at the height of the Cold War, when new — more harmonized and interoperable — systems were introduced to all countries of the Warsaw Pact.
Folding out the keyboard The lower part of the machine Close-up of the keyboard Front view of the amplifier. Below the amplifier is the cable storage compartment and below that the tuning-fork. The printer at the front left with its cover closed The printer at the front left of the machine Loading paper into the printer The closed machine (with the keyboard up) The opened machine (keyboard down)
Spare parts compartment just behind the printer Socket (behind the printer) for connection of the amplifier Amplifier cable Amplifier connected to the base unit 12V DC power socket and keyboard locking mechanism at the left side of the base unit Amplifier Rear view of the amplifier Dismantled vibrator unit

Controls and connections
The image below shows the ATF ready for use, as seen from the front. The keyboard is at the bottom right, with a rather small printer to its left. The printer is capable of printing text as well as morse code (dots and dashes). At the bottom left is a lever to select between teleprinter operation and morse code. To the rear of the printer is a small compartment for spare parts.

Font view of the ATF. Click for a clear view.

All connections to the outside world are at the front panel of the amplifier. From left to right are the sockets for connection of a field telephone, a morse key, a transmitter and the (telephone) line. At the far right are sockets for a pair of headphones (monitoring) and a ground terminal. A 125 Hz tuning-fork, needed for speed adjustment of the motor, is stored under the amplifier.

The machine is powered by a 12V DC source, such as the battery of a car, which is connected to a socket at the left side. Internally, the DC voltage is converted into AC by means of a vibrator unit (German: Zerhacker). As these are sensitive devices, a spare vibrator is present at the right of the cable storage compartment. The amplifier is connected to a socket behind the printer on the main unit by means of a thick cable that is usually stored in the cable storage compartment.
Early version
As it was strictly prohibited in the DDR to use former Wehrmacht nomenclature, the new machine was called ATF, which is short for Abtastfernschreiber (scanning teleprinter). The first version of the ATF appeared in 1952 and was built by the RFT consortium [1]. To this day it is unclear which member of the RFT group was responsible for the manufacture and/or which former HELL plants were used to source the components and knowledge from, but it was likely to be based in Berlin.

The extremely rare RFT ATF Schreiber. Photograph by Bernd Rothe [1].
RFT ATF Schreiber ATF-00001

The image above shows the initial version of the ATF Schreiber [1] as it was built by the RFT consortium in Berlin. It is the predecessor of the FFS-002. It is believed to be the only surviving sample of this machine and is part of the collection of the Military Historical Museum in Dresden.
The development of the RFT ATF Schreiber eventually led to a redesign of the final machine — the FFS-002-00001 — which went into production in 1954/1955, most likely in a factory in or near Berlin, as this is where the know-how and the parts from the wartime HELL production were located. It is currently unknown how many FFS machines were manufactured, but by studying the serial numbers of the surviving machines, it is possible to make an educated guess. Bernd Rothe estimates in his description of the FFS [2] that around 400 machines were produced, divided over two production runs. The following serial numbers are known:
  • 8009
  • 8018
  • 8067
  • 12232
  • 12275
  • 12320 ← our machine
The 4-digit numbers (starting with '80') are probably from a pre-production prototype run, the so-called XATF-Schreiber. These machines were later converted to KVP/NVA Feldfernschreiber machines. In total, the existence of 11 machines could be confirmed [2], 5 of which were more or less complete. The rest were just fragments that could only be used for spare parts. Of the remaining five machines, only two have been fully restored, one of which is part of our collection. The other one is in the collection of the Communications Museum (MFK) 1 in Frankfurt (Germany).
  1. MFK = Museum für Kommunikation (Communications Museum).

Although the ATF uses the same printing principle as the original Feldhellschreiber, the actual printer itself is constructed quite differently. First of all it is a lot smaller and it is driven by the main motor which is housed in the lower part of the machine, whilst the motor of the original Feldhellschreiber was placed vertically above the printer.
The image on the right shows the printer and paper path that are normally covered by a small hinged lid at the front left of the machine. A plastic window in the top lid allows the printing mechanism to be inspected without opening it.

A narrow paper strip is fed in from the paper compartment at the right, along a black metal strip. At the bottom is the ink roller which deposits its ink, via a small black roller, onto the square print head. The print head is pressed against the paper in the rhythm of the 900 Hz tone signal from the telephone line or radio.
Clear view of the pressure roller, the print head and the ink roller.

The major difference with the original Hellschreiber is the construction of the printhead. The print head of the ATF has four slightly curved sides, with a diagonally embossed line on each of the side surfaces, whereas the print head of the Feldhellschreiber is cylindrical with two embossed spirals on it. The effect is the same however, and results in two lines of text being printed.

The printer is driven by the main motor which is located in the bottom section of the machine. A collector's-find in Germany in 2008 [2] tells us that initially motors were used from the wartime production of the Rudolf Hell factory in Berlin-Dahlem. The motors were later reproduced by VEB Elektromotorenwerk Hartha (a.k.a. ELMO). The motor speed of 3750 rpm is stabilized by a centrifugal switch that can be adjusted with a small screw at the front of the printer, with the aid of a 125 Hz tuning-fork in combination with the stroboscopic disc at the front of the printer.
The printer at the front left with its cover closed The printer at the front left of the machine Loading paper into the printer Engaging the pressure roller to press agains the capstan Close-up of the pressure roller (left) and the square print head Clear view of the pressure roller, the print head and the ink roller. Front view of the printer The stroboscopic dic at the front of the printer

ATF Hellschreibers are extremely rare and therefore highly wanted collectors items. As far as we know, there are only six surviving examples of the FFS-002 and just one of the early RFT-ATF teleprinter. The latter is in the collection of Military Historical Museum in Dresden (Germany).
The FFS-002 featured on this page, was found on Ebay in May 2009. Although the machine looked allright in the photographs on Ebay, it appeared to be in bad non-working condition.

Luckily, our friend Bernd Rothe from Dessau came to the rescue. First of all he collected the machine from a small town near the Polish border, a return trip of 900 km. The machine was badly damaged by water, probably from storage in an old shed, and some critical parts were missing, but Bernd was determined to restore the machine and get it going again.
Bernd Rothe at work restoring our FFS-002

As the owner of the only working FFS-002 at the time, Bernd had sufficient spare parts to restore the machine and when we came to collect it a few days later, the driving mechanism was already running again. The image above shows Bernd at work in the small garage near his home in Dessau (Germany). And after another day of hard labour, the machine printed its first message.
One of the major difficulties was the driving motor. After years of storage, the main shaft had become blocked and was beyond repair. Luckily, an original refurbished HELL-branded motor was available as a drop-in replacement.

Another problem was the vibrator unit that is needed to convert the DC voltage into AC. After years of storage they become oxidised and are often beyond repair. For this reason a spare unit was normally supplied with the ATF. Although it can be replaced by a modern electronic variant, Bernd managed to repair the original vibrator.
The bare vibrator unit

We are most grateful to Bernd Rothe for his time, help and expertise when acquiring this ATF Schreiber and bringing it back to life again. For the restoration he used original parts from ATF fragments that he had found over time. Sadly, Bernd passed away unexpectedly on 1 December 2013 at the age of 66. He will be missed dearly. His ATF Schreiber is now part of the collection of the Museum für Kommunication (Communications Museum) in Frankfurt (Germany).
Vibrator unit Dismantled vibrator unit Interior of the vibrator Vibrator rear view The bare vibrator unit Bernd Rothe at work in his garage. In the foreground Peter Blühmer. Bernd Rothe re-assembling the ATF Bernd Rothe at work restoring our FFS-002

Technical specifications
  • Principle: ATF-HELL
  • Modulation: A2 ATF-HELL, A2 Morse Code (CW)
  • Tone frequency: 900 Hz (single tone)
  • Transmission: asynchronous (start/stop)
  • Transmission speed: 225 baud
  • Typing speed: 4 cps (characters per second)
  • Period: 250 ms
  • Raster: 56.5 fields with 7 lines each
  • Single line: 7 pixels
  • Information: 155.5 ms (35 fields of 7 lines each)
  • Start + stop: 94.5 ms
  • Pixel: 4.44 ms
  • Power: 12V DC
  1. Bernd Rothe, Der RFT ATF Schreiber ATF-00001
    2012-2013. Version 3.1. German.

  2. Bernd Rothe, Der KVP/NVA Feldfernschreiber FFS-02-00001
    2011-2013. Version 2.3. German.

  3. DV-44/14, Beschreibung und Bedienungsanweizung der Funkstation FK 1a
    Berlin, 1956. pp. 1, 3, 82-87. German.

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© Crypto Museum. Created: Wednesday 29 June 2016. Last changed: Saturday, 09 July 2016 - 09:26 CET.
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