| 摘要 |
An alarm signaling device (5) operable to produce an alarm signal and, possibly, communicate emergency announcements when triggered by a signal from a central alarm control panel. The alarm includes a speaker or other sound producing device and a silencing circuit (14) that can be engaged by a person in the room to temporarily disable the speaker. The silencing circuit includes a timing circuit (30) and a switch (32) consisting of a pair of touch contacts (38, 40) that are activated by body resistance. The timing circuit (30) is operable to automatically re-enable the speaker after a predetermined time period has been measured. Furthermore, though the speaker has been silenced by the silencing circuitry (14), a reactivation circuit (15) continues to receive and process signals in order to identify a re-enablement signal by its particular frequency and duration. Once the re-enablement signal has been identified, the reactivation circuit (15) automatically overrides the silencing circuit (14) so that alarm signals or emergency announcements may be communicated.
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