| 摘要 |
PURPOSE:To make a line switching operation easier by releasing and operating a power failure relay on basis of the button operation of a button telephone set when power is supplied. CONSTITUTION:When a particular number to indicate switching information through dial button operation of a button group 32 is sent, it is decoded and converted into operating data to indicate the switching information by the controller 34 and transmitted via the transmission circuit 35. When the data are received by the transmission circuit 9, the controller 10 judges them as the switching information, stops sending the control signals to the driving circuit 8, and releases the power failure relay PF. If a special number to indicate the release information is sent, it is transmitted as operating data by the controller 34 and circuit 35, and accordingly, the controller 10 restarts sending the control signals to the circuit 8. Then the relay PF is operated, the lines 21 and 22 are connected to channel switch 3 side, and outgoing and incoming through the lines 21 and 22 can be done freely by means of the telephone sets 231 through 23n.
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