Abstract: In a fully non-intrusive bus monitoring interface the bus under test is not affected at all by the presence of the bus monitor. Other bus devices do not recognize the monitor as it does not participate in the bus arbitration and tree identification. The bus monitor is completely invisible to the bus / devices under test as it is not assigned its own nodeID, does not transmit a SelfID packet and is not affecting the bus topology. Furthermore, the device does not add any delays into the signal propagation between two devices and has neglectable influence on signal quality. However, it still provides the necessary means to tap into the signal transmissions to detect bus symbols and convert them into suitable data patterns for subsequent data analysis.