Abstract: An apparatus and method for reliability testing an electrical connector for an unacceptable propagation delay. The propagation delay is detected in a transmitted test signal through the electrical connector in comparison to a reference signal having a known delay. A failure signal occurs in response to the transmitted test signal failing to transition before a corresponding transition in the reference signal. The apparatus and method is extendable to a plurality of conductor paths in the electrical connector, such as a parallel communication digital data bus. Moreover, the known delay in the reference signal is selectable for adjusting an allowable propagation delay criteria for applications with different data rate requirements.