| 摘要 |
PURPOSE:To attain the remote control of load through an optional telephone set without using any special control signal transmission means nor a call switch means, by using the ringing tone signals for transmission of the load control information. CONSTITUTION:After load 6 is inverted by the reception frequency of the ringing tone signal received from the control side in response to the 2nd dialing, the control confirmation signal Vg showing that the load control signal is outputted is sent in reply by the 1st reply means. The action confirmation signal Vg' showing the working state of the load 6 is sent in reply to the call delivered by the 3rd dialing. Thus it is possible to know completely whether the load 6 undergon normally the remote control or not. At the same time, the normal working of a load control means 5 is also confirmed. Furthermore it is possible to detect accurately a malfunction that is caused by mixing the calls given from other stations during a control action.
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