Abstract: A control system to provide digital printing and to plot an analog trace on an electric operated IBM model 11C Output Writer is described. The Digital mode of operation translates multidigit numbers through a set of commands to print each digit serially, then presents them to the output writer in a time sequence. The Analog mode of operation converts a d.c. input voltage to a digital number and by tab and space bar commands translates the carriage horizontally a distance proportional to this number.