The W48 wall-mounted telephone is the successor to the successful W36/W38 models. This device was developed in 1948 in post-war Germany for the postal service (Deutsche Post) in the western occupation zones, and mass production began in 1950 under the federal administration. Siemens & Halske played a significant role in both the design and manufacture of the device. Most components of the W48 are identical to those of its predecessors, the W36 and W38. Regarding color, the standard finish was black, although an ivory version was also available. In addition to Siemens & Halske, companies that manufactured the W48 wall-mounted unit in Germany included Mix & Genest, Krone—which produced a large number of W48 wall phones—and Richard Bosse & Co. Outside Germany, the W48 wall-mounted telephone was manufactured in Italy by OLAP, a Siemens subsidiary.