| 摘要 |
PROBLEM TO BE SOLVED: To provide a power switch system that uses a phone loop signal to control supply of power to a phone and attains a normal operation of the phone even on the occurrence of a power failure. SOLUTION: The power switch system is provided with: a rectifier (101) rectifying a phone loop signal to be sent to telephone lines (A, B) to produce a DC output; a latching relay for connecting either of power lines (G, H) to a power supply; and a differentiation unit (20) that excites an exciting coil (102) of the latching relay so as to connect either of the power lines (G, H) to the power supply when the phone loop signal is a call signal, and an integrator (50) connected between the rectifier (101) and the exciting coil (102) is discharged by a discharge control circuit when the phone loop signal is not a call signal nor a speech signal, the exciting coil (102) is excited by the discharge to interrupt either of the power lines (G, H) thereby deactivating a phone (103). COPYRIGHT: (C)2003,JPO
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