DV Series Optical Interactive WhiteboardSpecificationSensor Type Optical imaging touch technology Calibration 4 points Resolution 32768*32768 Sampling Rate 180PT/S Positioning Accuracy 5mm Scanning Speed First point:25ms,continuous points:8ms Transmission Speed 12m/s Working Temperature -20 to +60 Working Humidity 10% to 90% Power Supply USB Power less than 5V Operation System Windows XP/Vista/Windows 7/Linux/Mac DimensionsModel Size Aspect Ratio Overall Dimension(mm) Effective Writing Area(mm) DV-78 78" 4:3 1742*1281 1634*1173