Hand-operated printing machine for deaf and dumb - push button keyboard has shift button for alternative symbol

摘要

A keyboard has finger-operated buttons each of which can be used to print one of two different symbols e.g. a letter and a number. A shift button is operated to select which of the two symbols is to be printed. The shift button is placed on a surface of the printing machine which is not parallel to that of the keyboard. The selected symbols are printed out onto e.g. paper strip and can be read at the printing station with the aid of an illumination unit which can be switched on by the machine's main on-off control. The light output of the illumination unit is controlled by the output signals of a light meter measuring the ambient brightness.