Recommendation ITU-T K.44 seeks to establish fundamental test methods and criteria for the resistibility of telecommunication equipment 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 electric power lines or electrified railway systems, earth potential rise due to power faults, and direct contacts between telecommunication lines and power lines. Major changes compared with the 2008 version of this Recommendation include: - updating the references; - amended Criterion A; - revision of the test schematics to improve clarity; - adding test schematics for external coaxial cable ports; - adding multi-conductor test schematics for internal unshielded cables; - adding tolerances for waveform generation; - addition of ports that rely on insulation coordination for surge protection.