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Hellschreibers built by the Siemens-Halske company are discussed on this page.

If you have any additional information or documentation that would be appropriate for this particular page, please contact me.

Note that all major teleprinter manufacturers (e.g., Siemens, Lorenz, Creed, Morkrum-Kleinschmidt/Teleteype) produced teleprinters that print on paper tape, but that are not Hellschreibers. However, some did develop and manufacture Hellschreibers. They are discussed on my "Other Manufacturers" page.

[1929 electro-chemical printer]   [NS2 and NS3]    [HE-5 and HE-6]    [U-Boat Hell printer]    [ZETFAX]

Rudolf Hell's first Hellschreiber prototypes used electro-chemical printing, without a spinning helix. The paper tape was impregnated with yellowish potassium ferrocyanide (prussiate of potash, "gelbes Blutlaugensaltz"). The tape had to be moist, so as to be conductive to electrical current. Passing current through the salt solution caused it to change color, by decomposing it into a compound called Prussian Blue ("preußisch Blau", "Berlin Blau").  Instead, it had 14 styluses, placed into a column across the paper tape, touching the tape. Current could be sequentially applied to each individual stylus ( = scan), the current circuit being closed via the moist paper tape and a metal roller underneath the tape. This form of printing proved impractical: the paper tape had to be kept moist, it had an unpleasant smell, and the chemicals would cause the paper tape to fall apart, dried paper tape would shrink, and printed text faded (ref. 6).

Prussian Blue dye was used since the early 1700s, including for dyeing the cloth used for the uniforms of the Prussian military - hence its name. It is also the characteristic color of "blueprints": copies of technical drawings, based on a photochemical process involving Prussian Blue, widely used in the decades preceding the modern photocopier.

1929 prototype with (electrochemical) printing on chemically impregnated paper tape
(figure 2 in ref 1.)

Note that electro-chemical paper tape printers where not new. Such printers - though with a single stylus - were used for "Morse" telegraphy printers since the 1830s. Alexander Bain patented an electro-chemical copying-telegraph in 1843. In the early 1930s, an electro-chemical paper tape audio recorder/player was invented (ref. 4, 5).

Electrochemical paper tape telegraphy printer by Alexander Bain (ca. 1846) - up to 1000 WPM
 

Electrochemical paper tape telegraphy printer by Du Moncel (ca. 1850)

As stated above, this printing method did not use a printing helix, and was impractical. It was abandoned in 1931, in favor of the first generation Hell-printer that did have a printing helix. This spindle was used to transfer carbon particles from a carbon-covered tape onto the actual printing-paper tape. It was manufactured by Siemens-Halske, and is described on the associated page.

	Ref. 1: "Die Entwicklung des Hell-Schreibers" by the inventor himself: Rudolf Hell; pp. 2-11 in "Gerätentwicklungen aus den Jahren 1929-1939", in "Hell - Technische Mitteilungen der Firma Dr.-Ing. Rudolf Hell", Nr. 1, Mai 1940   [in German].
	Ref. 2: "Stand der Siemens-Hell-Fernschreibtechnik", R. Zimmerman, Siemens & Halske A.G., Siemens Fernmelde Technik, SH 7997. 0,5. 1043. TT1.  M/1401 (1940?), courtesy Siemens Corporate Archives, München.
	Ref. 3: "Der Siemens-Hell-Schreiber", Alexander B. Damjanovic, Zeitschrift für Fernmeldetechnik, Werk- und Gerätebau, Siemens & Halske A.G., Wernerwerk, Jg. 17, Nr. 12, 1936, 7 pp., SH 6554, 1. 37. 0,5 T.
	Ref. 4: "Method Of And Apparatus For Electrically Recording And Reproducing Sound And Other Vibrations", Merle Duston, United States Patent 2,030,973, filed: 13-Aug-1931, awarded: 18-Feb-1936
	Ref. 5: "Record Of Voice Now Made On Moving Paper Tape", Popular Science, Volume 124, Nr. 2, February 1934, p. 40
	Ref. 6: §2 of "Anwendung von Faksimile-Hellschreibern für den Boden-Bord-Verkehr", Rudolf Hell, pp. 67-75 in "Flugsicherungs-Verfahren und -Technik: Grundsätzliches über die Technik für Flugsicherung und Betrachtung der wichtigsten technischen Hilfsmittel außer Radar“, Teil IIIB in "Flugnavigation und Flugsicherung“, Band 7 of "Bücherei der Funkortung“, proceedings of the "Internationale Jahrestagung des Ausschuß für Funkortung“, Berlin; Verkehrs- und Wirtschafts-Verlag, 1958, 107 pp.

The Hell company built a series of Hellschreibers for the Kriegsmarine. The type designator is "NS" followed by a one digit number. Shown below are the NS2 and NS3. I have no information about NS1, or if there ever was an NS4, etc.

"S" in "NS" stands for "Schreiber". I do not know what the "N" stands for. They are painted standard navy gray. The NS-keyboard differs slightly from that of the Hell Feldfernschreiber: it has an "=" sign, instead of the pause character.

The telegraphy speed of these machines is unknown (2.5 or 5 characters/sec).

The units are operated off 220 Vac power. This is the standard ship-board power for German navy ships and submarines (when not running on batteries). E.g., the famous battleship "Bismarck" had four  power plants: eight diesel generators, and six turbo-generators. In total almost 8 megawatt of DC and 220 VAC power (this ship was enormous in many ways, including the price: an estimated €750 million - the equivalent of some 35 submarines)! As the NS units used 220 Vac, they did not need the generator part of the Feld-Hell's 12 VDC dynamotor to generate anode voltage for the tubes.

Hellschreiber type NS2

(original NS2 photos: courtesy David Hamar, NSA National Cryptological Museum, 2010)

Tag on front of Hellschreiber type NS2

Hellschreiber type NS3

(original NS3 photos: courtesy Niels Juel, 2011)
 

Tag on front of Hellschreiber type NS3
 

Right-hand side of Hellschreiber type NS3
 

Tag on right-hand side of Hellschreiber type NS3
 

Rear view of Hellschreiber type NS3

Apparently, in 1948 the Hell company used parts of other machines to manufacture a small number of two Hell Scheiber Empfänger models ("printer-only" Hellschreibers): HE 5 and HE 6. I.e., they did not have a Siemens-Halske model number "T empf".

 If you have any additional information or documentation on these models, please contact me!

It is possible that the 1947 printers shown below are in fact HE 5 or HE 6 printers...

(source: Hell Verein Kiel)

The "Großer Delphin" class U-Boat (2-man submarine; may not have entered into active service) was supposed to be equipped with a "Kreiselkompaß mit Hellschreiber" (ref. 25). I.e., a gyro compass, combined with a Hellschreiber printer.

If you have any information or documentation on this model, please contact me!

Ref. 25: p. 709 in “Die deutschen Kriegsschiffe 1815-1945 , Band 2“, Erich Gröner, J. F. Lehmann Publ., 1966, 870 pp.

Around 1960, Hell developed an optical-scan paper-tape fax system. These machines were used by Air Traffic controllers (to exchange flight info strips), weather services at airports, police (to transmit fingerprint cards), restaurants, factories, labs, etc. It is called ZETFAX, short for "Zettelfax" ("Zettel" = note, slip of paper). The equipment is fully transistorized.

ZETFAX "Geber" (sender) and "Schreiber" (printer)
(note the classical printer mechanism in the receiver on the right)

On the sender side, text is handwritten onto paper tape. The paper tape is pulled through an optical column-scanner. Light from a small light bulb is passed through a special lens that casts a bar of light across the tape. The light bar that is reflected off the paper, is passed via simple optics through a narrow slit and a spinning Nipkow-disk ("Spiralblende"). The holes in the disk effectively "chop" the column-scan into light pulses. These (moving) pulses are are detected with a window-type photomultiplier tube of type 931A (ref. 39).The analog brightness signal from the photo-tube is passed through a level-detector (threshold). The resulting binary DC-pulses are converted to tone-pulses and sent to the printer at the opposite station. The 800 volt anode voltage is generated with a 10 kHz oscillator and transformer-rectifier.

The scanning-disk has an additional hole at the circumference. With a light source and a photodiode, this creates a start-pulse (one per revolution of the disk), to synchronize the sender and the receiver/printer. On the printer side, this (dis-)engages a clutch on the printer spindle.

The printer is basically a classical Hell spindle-printer. It has a spindle with a 1-turn thread. It uses the same type of paper tape as the the sender.

Printer module of the Hell HT 207 ZETFAX-Schreiber

(item 7/2 = printer spindle, 7/3 = spindle thread, 7/4 = felt ink roller, 7/5 = solenoid hammer)
(source: figure 7 in ref. )

Both sender and printer unit have a synchronous AC-motor (brand: Papst Motoren GmbH, type "Außenläufer" ("squirel cage")). In "modern" countries, the power plants that feed the 50/60 Hz public power grid, are tightly synchronized. This minimizes speed differences between a sender and printers that are connected to such a national (or international) power grid.

As with other Hellschreibers, transmission can be done via phone lines and radio. ZETFAX can be used in uni-cast as well as multi-cast configuration (1 sender to many printers).

Characteristics:

	Paper-scan and transmission speed: 19 cm/min (7½"/min) @ 50 Hz, 23 cm/min (9"/min) @ 60 Hz
	Image resolution: 4 lines / mm (102 lpi)
	HT206 (paper-tape scanner/sender) - scanner paper input : paper width: 38 mm (1½") paper length: 66, 102, or 152 mm (2.6-6") scanned width: 25.4 mm (1")
	HT236 (paper-piece scanner sender) - scanner paper input : paper width: 38-135 mm (1½ - 53") paper length: 50 - 500 mm (2 - 20") scanned width: 27 mm (1.1")
	Printer paper output: 38 mm (1½") wide paper tape printed width: 25.4 mm (1") in combination with HT206, 27 mm (1.1") with HT236
	Tone frequency: 1500 Hz +/- 700 Hz
	Equipment size (HxWxD) and weight: HT206 (tape scanner): 14x36x34 cm (≈ 5½x14x13"), 14 kg (≈ 31lbs) HT236 (piece scanner): 18x36½x37 cm (≈ 7x14x15"), 16 kg (≈ 35lbs) HT207 (tape printer):     15x22x31 cm (≈ 6x9x12"), 9 kg (≈ 20 lbs)

The ZETFAX machines were developed and built by the Hell company. However, at least in some parts of the world, the ZETFAX was marketed, sold, and supported by Siemens; e.g., in Singapore and Malaysia (see advertisement further below), and in Spain. In 1968, the Spanish Air Ministry ordered 25 Hell ZETFAX HT206 senders and 50 HT207 printers - plus enough spare parts and supplies for two years - from Siemens Industria Eléctrica S.A (ref. 37). The equipment was used by the national meteorological service. Total cost was 5 million pesetas in 1968. This is equivalent to almost 347 thousand euros (465 thousand US dollars) at the end of 2011, based on historical exchange rate data (ref. 38a) and historical US inflation data (ref. 38b). 

Listed below are Hell patents related to the optical scanning and transmission of text printed on paper tape.

ZETFAX-Geber Typ HT 236 (left) and ZETFAX-Schreiber Typ HT207 (right)
 

Examples of handwritten ZETFAX strips (blank paper and and preprinted forms)
(aerodrome meteo report, 2x lab analysis results, hotel breakfast order; source: ZETFAX advertising brochure)
 

(source: ref. 33)

1965 ZETFAX advertisment
(source: ref. 36)

References:

	Ref. 31: "Nog een hell-systeem", A. van Ooijen, PE1AQB, Electron, 8/1983, p. 417 [optical Hell, ZETFAX]
	Ref. 32: "ZETFAX, aus der Praxis, für die Praxis" [Hell Co. optical-scan + Hellschreiber tape printer], Rudolf Hell GmbH, 1968, 19 pp., ZA-2-6807(592).
	Ref. 33: "Interavia: world review of aviation-astronautics-avionics", vol. 22, nr. 6, 1967, p. 913
	Ref. 34: "ZETFAX - Faksimile Geräte", Hell Co. brochure Z-4-6611 (502), 6 pp.
	Ref. 35: "Vermittlungs-Einrichtungen ZETFAX”, Hell Co. brochure ZV-1-6704 (534), 6 pp.
	Ref. 36: p. 21 in The Straits Times, 9 November 1965, Advertisements Column 2
	Ref. 37: p. 17508 in "Boletín Oficial del Estado" (Spanish government gazette), Nr. 293, 6 December 1968
	Ref. 38a: "Foreign Currency Units per 1 U.S. Dollar, 1948-2009", Pacific Exchange Rate Service of the Saunder School of Business at the University of British Columbia
	Ref. 38b: "Cumulative US inflation for the period 1968 - November 2011"
	Ref. 39: "913A, 913B photomultiplier", product brochure of Burle Electron Tubes, 6 pp.
	Ref. 40: "ZETFAX-Schreiber HT 207; Wartungsvorschrift und Ersatzteilelist" [maintenance manual, parts list, schematics], Hell Co. document 207-WE2-6411, November 1964, 35 pp.   (courtesy Arie, PE1AQB)   [17 MB]
	Ref. 41: "Elektrische Wirkungsweise" [schematic +  hardware functional description], chapter 2 of "ZETFAX-Geber HT 206" maintenance manual, Hell Co. document (courtesy Arie, PE1AQB)

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