In the early years, the Swiss Army ordered transmitters from the C. Lorenz AG in Berlin-Tempelhof; the single receiver ordered from Lorenz was the EO 509 / I. Also during the post-war years, Lorenz transmitters were in use; later the company became SEL (Standard Elektrik Lorenz).
Carl Lorenz was the founder of the Telegraphenbauanstalt in 1880, morse equipment and arc lamps were manufactured. After his death, the company was taken over in 1890 by Robert Held and 1906 after acquisition of another telegraph construction company; the C. Lorenz AG was founded, a license agreement with the Amalgamated Radio Telegraph Company gave access to the Poulsen arc transmitter technology.
In addition to Poulsen arc transmitters and machine transmitters, Lorenz constructed telephones and teletypewriters. In 1920, a broadcast transmitter constructed by Lorenz started operation, radio receivers were added to the companies offerings. In 1927, the Lorenz company could acquire patent rights from the estate of E. Huth Radio company.
In May 1930, the majority of the shares were sold to the Standard Electricity Company, which was a branch of the American ITT; the Lorenz AG acted largely independent of it's parent company until 1945 and provided communications equipment to the German police, Reichspost and Reichsrundfunkgesellschaft (German Reich Broadcasting Corporation), Lorenz became a large scale producer of military goods.
In the thirties, Lorenz developed a wire recording device, telegraph and broadcasting technology were the main products of the group.
After World War II, the production was moved from the parent company plant in Berlin-Tempelhof, to production sites in Hannover, Landshut, Pforzheim and Stuttgart, where in 1949 the company headquarters were moved to. Mainly radio sets of the brands Schaub and Lorenz and the wire recorders „Recordophone“ were produced.
In 1958, within the ITT group Standard Elektrik AG was merged with C. Lorenz AG to become Standard Elektrik Lorenz (SEL). In 1961, Graetz from Austria joined the group. After a decline in the 1970s, the new owner Alcatel sold the SEL to the Finnish Nokia.