Abstract: A system and method for calibrating testers. A reference timing signal and an internal timing signal used in tester calibration are generated within a tester. A first calibration is performed wherein test module channel characteristics are measured and recorded, and an adjustment value is determined to correct the time placement of the internal timing signal. Driver and receiver delays are adjusted based on the characteristics measured in this first calibration, and the internal timing signal is adjusted as well. A second calibration is performed wherein temporal relationships between the adjusted internal timing signal and signals at the test module channel mint pins are determined. Driver and receiver delays are adjusted based on the results of this calibration. An optional calibration is performed wherein temporal relationship between the adjusted internal timing signal and signals at the board-interface end of a test fixture are measured.