To use the OPB732CZ sensor, plug it into the 4 pin Molex connector on the calibration board. Next, set the phototransistor load resistance to 9.6 Kohms by positioning the shorting bar on the board betweens pins 2 and 3. To begin the calibration process, point the sensor at a sheet of white paper and position its front surface about ½ ” from the paper. While holding the sensor in this position, momentarily ground pin 4 of connector J1 to initiate the calibration process. After approximately 2-3 seconds the green LED should flash three times to indicate that the sensor has been calibrated for that distance. If the sensor calibrated correctly, there will be no LEDs lit on the calibration board.