| 摘要 |
An improved telephone alerting system (2) that includes at least one triggering device (4, 6) that senses an unsafe condition and generates an electrical signal in response to the unsafe condition. The signal is applied to an electronic circuit consisting, in part, of a timer (8) and a relay (10). When the relay is energized, a signal is passed that activates a telephone set (34), where the system is installed, and opens the telephone cradle switch (12). The activated telephone automatically calls one or more preselected telephone numbers. Thus, when the person answers one of the preselected numbers, the person is able to hear, through the open cradle switch, the events occurring at the protected location where the system (2) is installed. The system (2) therefore indicates the current status of the protected premises without complex circuitry. |
