a shift control system for keyboard having plural character keys and at least one shift key arranged in a predetermined key matrix and the positions of which are defined by respective matrix codes , including a keyboard controller under the control of a central processing unit for determining a depression of any of the keys of the key matrix . the matrix codes of the shift keys are predetermined and so identified . the key matrix is scanned and the matrix codes of any depressed keys are determined and compared with the predetermined matrix code of the shift keys . keycodes are formed for each depressed key based on the matrix codes produced for the respective key and based on whether or not a shift key depression is determined .