When it approaches the workpiece surface, the stylus deflects and a trigger signal is transmitted to the receiver by infrared light. Interference-free signal transmission between probe and receiver is necessary for reliable measurement and is carried out by HDR. High-speed technology avoids interference caused by ambient light from inside and outside the work area. A frequency of 75 Hz is used and a high data rate of 9,600 light pulses per second prevents interference from the machine lamps. Adjustable transmission power and angles, wide reception angles and microprocessor control make it perfect for infrared light evaluation.