Recommendation ITU-T K.65 specifies the overvoltage requirements and test procedures for termination modules, with contacts for test ports or surge protective devices (SPDs), used for symmetric pair conductors subjected to overvoltages and overcurrents. Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction of alternating voltages from adjacent power lines or railway systems, earth potential rise due to power faults, and direct contacts between telecommunication lines and power lines.