Title:
DANGER ALARM METHOD AND APPARATUS
Document Type and Number:
Japanese Patent JPS59218595
Kind Code:
A
Abstract:
In an alarm system a central signal station periodically transmits interrogation signals, preferably in the form of infrared radiation packets to remotely located detectors which transmit a response signal back to the central signal station after differing time delays that are characteristic for the individual detectors and which permit the localization of the source of the response signal. In an alarm state, the detectors respond to every interrogation signal, in the normal operational state to only every mth interrogation signal, i.e. less often, and in a state of diminishing battery potential to only every small pth interrogation signal, i.e. even less often. The state of the individual detectors is determined from the frequency with which the response signals are transmitted back by the detectors, that is the ratio of the response signals to the interrogation signals.
Inventors:
ARAN POORU TORUUPU
HANNESU GIYUTSUTEINGAA
GUSUTAFU PUFUISUTAA
HANNESU GIYUTSUTEINGAA
GUSUTAFU PUFUISUTAA
Application Number:
JP8763084A
Publication Date:
December 08, 1984
Filing Date:
April 28, 1984
Export Citation:
Assignee:
CERBERUS AG
International Classes:
G08B26/00; G08B25/00; G08B29/16; G08B29/18; (IPC1-7): G08B25/00
Attorney, Agent or Firm:
Michiteru Soga
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