| 摘要 |
Electrically conductive leads electrically connect a relay, a source of electrical energy and a radio transmitter for transmitting radio signals in a back up circuit. The relay is electrically connected to the electric circuit of a burglar alarm system. When an electrical conductor of the burglar alarm system is cut, the relay closes the back up circuit to actuate the transmitter to transmit radio signals indicating that an electrical conductor of the burglar alarm circuit has been cut.
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