The A200-2 set consists of two sensors which allow for potential free transmission of analog signals under EFT/ESD/RF interference. The signals are displayed on an oscilloscope. Disturbed signals can be easily detected. In the device under test the sensor transforms the measured logic signals into optical signals. The optical signals are transmitted via a fiber optical cable to the optical receiver which transforms them into electrical signals. These can be seen with an oscilloscope or can be used for controlling other devices. The system is suitable for monitoring signals or devices under test in an anechoic chamber or for EMC optimizing of hard- and software.