To improve the performance of a standard monitor interconnect, e.g., a VGA monitor interconnect, a display adaptor of a computer device generates reference signal patterns which are used to calibrate the signals received by an interconnected display monitor. The monitor receives the reference signal patterns from the computer over the interconnect with the analog display signals, e.g., during the blanking intervals of the signals, and adjusts the signals based upon a detected deviation of the reference signals from corresponding control values. In one embodiment, the computer device generates and sends reference signal patterns if it receives from the monitor confirmation that it is equipped to perform calibration based upon received reference signal patterns, and operates normally (without reference signal pattern generation) otherwise.