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A metal device for calls and signals in grey colour. Metal base for fitting in a telephone exchange. The calls and signals device from Lorenz company (the predecessor of SEL-Standard Elektrik Lorenz and later ITT-Germany) was manufactured around the beginning - middle of 1950 and was used in telephone exchanges. The device covered many functions, aside from the role as generator for telephone calls and signals, providing electricity for the function of the telephone lines, regulating the sound with the frequency at 450 Hz and mechanically regulating the speed at which the numbers and lines were chosen. It was used in telephone exchanges, constituting one of the basic parts of their equipment. There were usually two, one always being on stand-by which, in case of failure of the first, began to operate automatically.