PROTECTIVE DEVICE AND COMMUNICATION DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain information concerning a state in which a communication device connected to a communication line or a power line is protected from a surge current. SOLUTION: Sudden increases in currents caused by the sudden increases in voltages, generated in communication lines L and/or power lines E, are picked up by toroidal coils 21, and currents outputted by the toroidal coils 21 are supplied to a current detection unit 22. The current detection unit 22 converts the currents from the toroidal coils 21 into voltages and supplies the voltages to a switching circuit 23. A switch circuit 11 turns on an indicator lighting circuit 24 for a certain time to cause the LED 25 of the indicator lighting circuit 24 to light.