| 摘要 |
PURPOSE:To ensure the operation of relay and to reduce the power consumption, by making the power for driving relay available with the charging voltage of capacitor and monitoring the charging state. CONSTITUTION:The power supply 29 for relay drive of terminal device is made with the charging voltage of the capacitor C charged with the DC voltage rectifying the transmission signal. The relay is excited when the signal outputted from the detection circuit 35 detecting that the terminal voltage of the capacitor is a given value or more and the change detection signal outputted from the circuit 36 detecting the change in the latch control signal are obtained at the same time. Further, when the terminal voltage of the capacitor is less than a given value, if the latch control signal is changed, the rapid charge circuit is operated and the capacitor is charged, frequency relay drive can be made. |
