| 摘要 |
The system includes a device ( 1 ) for detecting hung up/picked up line, which provides a signal showing whether the line is open or closed, a device ( 2 ) for closing or opening the line ( 7 ), which provides the data to be transmitted, a device ( 3 ) for detecting a conventional call, a module ( 4 ) for exterior connection, a power supply circuit ( 5 ), which receives electrical current from the telephone line ( 7 ) itself and control means ( 6 ) which, on receiving a signal through the connection module ( 4 ), transmit an appropriate signal to the device ( 2 ) for closing and opening the line ( 7 ), which transmits the data of a message to be transmitted.
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