Embodiments of the invention include testing arrangements for detecting proper DC-coupled board connections on the input legs of a differential receiver. The testing implementation includes a first test receiver AC-coupled to the connection between the first input/output (I/O) pad and the differential receiver positive input and/or a second test receiver coupled to the connection between the second I/O pad and the differential receiver negative input. The test receiver protects the test receiver input from DC voltages applied to the differential receiver via the differential receiver input. Also, the test receiver includes a high-pass filter arrangement that generates data capable of detecting whether the I/O pad connected to the test receiver has a proper DC-coupled connection or an improper connection when presented with a stimulus pulse. The test receiver is less susceptible to noise because than conventional arrangements that use a low-pass RC filter.