Voss portable typewriters were manufactured beginning in 1948 by Wuppertaler Schreibmaschinenfabrik, Voss GmbH, in Wuppertal West Germany.  This company later was apparently divided more fully from its parent, and known as Voss Schreibmaschinenwerk.  New details of the various models and history have come to light, thanks to collectors Thomas Furtig, Norbert Schwarz and Mike Fritch, as well as the German online collectors' group known as Historichesbuero.
It is diffucult to properly identify these machines by model, since various models over time used different body styles.  For example, the machine seen above right is in the body introduced by the Model 52 in 1952; however, it is actually a Model ST-24.  We will briefly delineate body styles, and model numbering, so that some general perception can be attained.
Body styles, in order of production, are as follows.  First was a very pre-war looking design, which may or may not have had covered ribbon spools, depending upon model.  Some have a decal with an illustration of the Wuppertal monorail; a drawing of this same landmark is seen as found in a much later Voss sales brochure.  Next body style to be introduced was the type seen above, with swoopy lines and gull-wing ribbon spool doors.  Next was a similarly shaped design which had a large, one-piece solid top cover.  Last was the Voss Privat, actually a member of the "Oliver Courier" or "Euro-Portable" family, which will be discussed on another page.
Left, 'gull wing' door on Model 52 and later machines until introduction of the later style with one-piece top cover, seen illustrated on the right.  It is not known when the body style break happened, or whether there was any overlap.  Right, Voss M-10.
According to Thomas Furtig, model numbering was as follows.  Early machines, for the first several years, were given model numbers concurrent with the years in which they were made.  Thus, a 1948 machine was properly a Model 48.  There are some Model 48 machines which also carry the label 'Klein-Voss.'  It appears from my data that there was an intermediate period which used M series models; the one-piece top cover machine seen above right is a Model M-10.  The Business-Riter, seen later here, is Model M-13.  Late machines have a coded model system, beginning with S.  The ST series added a tabulator, and SDT had the decimal tabulator seen below.  Following that was a number indicating platen length in centimeters; thus, the very simplest machine would have been an S-24, and the top of the line machine an SDT-32.
A simplified version of the S-24 was known as the Voss Karin.  We do not yet know a break point for dating of model changes, although the change from the year code to letter code had happened after 1953 and before serial number 109926 was reached.
Voss sold no machines of truly standard, or office size but did market its biggest machines as office typewriters, as we can see here.  This is the M-13 Business-Riter.  There was also an even more expensive System-Riter, not seen here.
If you're lucky, you'll find a fully optioned machine with dust cover, and accessory case with dust cloth and brushes, seen here.  There's also a felt pad for the machine to sit on.
all pictures this page by Will Davis
Next Page:  History of the Voss company.