Soemtron History

Sömmerda coat of arms

The German "Rheinmetall" heavy engineering works was established by Heinrich Ehrhardt in Düsseldorf in 1889 as the "Rheinische Metallwaren und Maschinenfabrik Aktiengesellschaft" (Rhein Metalwares and Engine Works Corporation) and registered on May 7th 1889.  In the same year production started in rented accommodation in Dusseldorf's Talstrasse, and almost within a year they are employing 1,400 people producing 800,000 bullets a day.  In 1901 a munitions factory was then acquired in Sömmerda, a small town near Erfurt in Thuringia, Germany, on the Unstrut river.  Following the first world war the Sömmerda factory started producing office machines, typewriters, mechanical calculators, adding and listing machines, they continued to further develop their range of machines upto the second world war in 1939-45.

Following the second world war, the Sömmerda factory then found itself in the newly formed East Germany, with development and production now continuing as a state-run enterprise, but using the pre-war Rheinmetall name and logo.  In 1957, a group of young electronics engineers under the collective direction of Heinz Skolaude brought V.E.B. [1] Büromaschinenwerk [2] Sömmerda into the age of electronics.  In 1960 the name was changed to "Supermetall" and then later to "Soemtron" in 1962, when they exhibited at the Leipzig Fair of that year an electronic Fakturierautomaten [3] - the model EFA 380.  1963 saw the next model the EFA 381 with magnetic core memory.

When the new brand name "Soemtron", composed from the words "SOEM"merda and Elek"TRON"ik, appeared, the long running legal dispute with the Düsseldorf Rheinmetall Group to the trademark "Rheinmetall" was resolved, along with use of the company logo and patent rights.  Previously to this, machines were sold under the trade name Supermetall.  In 1966 V.E.B. Büromaschinenwerk Sömmerda then released the first of three electronic calculators.  These models, with germanium transistors and Ferritkernspeichern [4], were produced in several versions - the ETR 220, the ETR 222 (which entered production in 1968), and the ETR 224.  From 1968 onwards electronic invoicing and accounting systems were introduced including the EAA 382 and EAA 385 systems, and in 1971 the production of printers began.  Production of mechanical calculators ceased at the factory in 1967 with the firm moving over to full production of electronic calculators, mainframe and personal computers like the 8-bit computer model 1715 and latterly the Soemtron 286 and 486 PC's right up until they finally ceased all production in December 1991 having failed for many years to keep up with the western world's dramatic advancements in electronics and computing.

With around one million computers, calculators and office machines, V.E.B. Büromaschinenwerk Sömmerda was probably the largest manufacturer of mechanical and electronic computing technology in the eastern Bloc.  Much of the information summarized here originates from a book by Annegret Schule, "BWS Sömmerda" (Desotron Erfurt 1995 ISBN 39-8039-311-9), which describes the history of the enterprise in some detail.  Further information and numerous photos of the different Rheinmetall-Soemtron models can be found in a book by Alfred Waize, "Die Welt der Rechenmaschinen" - "The world of the Calculating Machines" (Desotron Erfurt 1999 ISBN 39-3287-509-5).

Manufactured from 1966 to 1977 by V.E.B. Büromaschinenwerk Sömmerda, the Soemtron ETR series of calculators are by modern standards very basic six and seven function calculators with a 15 digit Nixie tube display or mechanical print mechanism.  Three different units (and possibly four) were produced in the eleven year production run of these increasingly rare early electronic calculators from the Eastern Bloc.

• The ETR 220 - with six functions and three temporary registers, it is the most common machine in the range even today, with over 155,000 produced by V.E.B. Büromaschinenwerk Sömmerda in the 11 years between 1966 to 1977.  Technical information for the 220 is rare but manuals, circuits and information in several languages do turn up from time to time.
• The ETR 222 - with six functions and again three temporary registers, just over 3,000 type 222 calculators were manufactured between 1970 and 1972, this machine is rarely seen on the open market, and to date no documentation for the 222 has been found.
• The ETR 224 - a very, very rare machine with just over 500 units being produced in the six years during 1968-1974.  The 15 digit nixie display is replaced with a 16 digit mechanical printer mechanism (15 digits + decimal point).  The Soemtron 224 electronics appears to be based on a heavily modified version of the 222 calculator, with additional control electronics for the printer.  It would seem that no technical information now exists for the 224, and no machines are known to exist in the wild, other than the only known example in the Sömmerda Historisch-technisches Museum im Dreyse-Haus Weißenseer, Sömmerda.

Rumors continue to surface about the existence of a fourth ETR type, the extremely rear ETR 221, another printing variant like the 224 but split into two housings with a long umbilical cable.  One machine apparently existed in London at the offices of the UK importers "Office and Electronic Machines".  Further information about the 221 can be found on the 221 page from the menu links above.

The Soemtron series of calculators were imported into the U.K. from the D.D.R. by a company called "Office and Electronic Machines", who were based in London, but with the advent of small calculators using logic chips or basic processors during the eleven year production run of the Soemtrons, their sales market and use was mainly restricted to Eastern Bloc countries.

Film -
Several Soemtron ETR 22x type calculators appeared in a 1977 Russian film - "Office Romance" directed by Eldar Ryazanov.  A Wikipedia entry for the film can be found here, and stills from the film showing the Soemtron's can be seen here, and also at the Wikipedia website.

Legal -
We have a copy here of an export permit that Bernard Green of Office and Electronic Machines used in 1967 to export various manuals and documentation from East Germany.

In 1959 and 1960 Walter Kasper of VEB Elektronische Rechenmaschinen Wissenschaftlicher Industriebetrieb Karl-Marx-Stadt, as the inventor, applied for patents in Germany, France, England and Holland for a "Calculating Device" for the serial addition or subtraction of two binary numbers with BCD correction.  The patents are - (with date filed / date granted) -

Advertising -
Bernard Green has sent in an advert that appeared in "Office Methods and Machines" July 1967, as a "New desk calculator with 15 digit capacity and three independent accumulators".  A copy of the advert is here.

The Soemtron 220 range also appeared in the "Büromaschinen Lexikon", a German technical publication covering office machinery and related products.  Soemtron branded products appeared in all the issues between 1962 and 1969 but only three entries are available online below -

Personal -
We have started a small section here for personal thoughts and recollections of Sömmerda, the Soemtron brand and it's people.  To kick this section off the first is from Bernard Green who was Senior Engineer at Office and Electronic Machines in London UK, importers / exporters of the Soemtron series calculators.  Has sent us his recollections of his time at the factory and it's influence here.

If you have any further historical information, circuits, drawings, photographs, data or manuals about the Soemtron ETR 220, 221, 222, 224 or their manufacture, test equipment (Prüfgeräte) or you just know more about the Soemtron companies in general then please let us know, contact us here.

Some of the information on this page has been derived from www.robotrontechnik.de with grateful thanks.