4ITU-T K.9 Protection of telecommunication staff and plant against a large earth potential due to a neighboring electric traction line(通信维护员工和设备对邻近电气化铁路接触网引起的地电位升的防护).
5ITU-T K.26 Protection of telecommunication lines a clainst harmful effects from electric power and electrified railway lines(电力线和电气化铁路对通信线路产生的有害影响的防护).