| 摘要 |
An alarm module is provided that includes a first and second switch, a power source and a signal module for generating an alarm signal. When the first and second switch are both in the closed position, the signal module is activated by power from the power source. The first switch opens when an item associated with the alarm module is placed on or connected to the alarm module, and closes when the item is tampered with or removed. The second switch opens when a key is inserted into the alarm module, and closes when the key is removed from the alarm module. The alarm module may also include a third switch that closes when power flows from the power source to the device, and can only be opened upon insertion of the key into the alarm module.
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