Safeguard device with coded transmitted signal
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United States of America Patent
Stats
-
Dec 31, 1991
Grant Date -
N/A
app pub date -
Sep 25, 1989
filing date -
Sep 27, 1988
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A safeguard device having a transmitter produces a high-fequency signal modulated with a code signal word and a receiver having an alarm device is controlled thereby. To protect the transmitter from unauthorized use and to achieve an expansion of its utility, a switching device is provided having a memory for storing a code word and an input unit for a password. The switching device includes a comparing device and code signal generator. The comparing device enables the transmitter when an input password matches with a stored code word. The code signal generator selectively produces either an alarm or a reset code signal word to modulate a high-frequency signal. When the transmitter is switched to the active transmitting state, the appropriately modulated high-frequency signal is emitted. At the receiver, the alarm device is either activated or switched off depending on the code signal word received.
First Claim
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Patent Citation Ranking
- 14 Citation Count
- H04Q Class
- 0 % this patent is cited more than
- 34 Age