Secure personnel monitoring system
First Claim
1. A personnel monitoring tab comprising:
- (a) an object incorporating means for emitting a signal;
(b) fastening means for attaching said object to the body of a person to be monitored;
(c) indicative means having an tamper state and a non-tamper state, said indication means being switchable from said non-tamper state to said tamper state, indication means including means for altering said signal while in said tamper state;
(d) latch means for retaining said indication means in said tamper state after said indication means is switched into said tamper state; and
(e) sensor means for detecting detachment of said object from the body of the person and switching said indication means from said non-tamper state to said tamper state when said object is detached from the body, said latch means being operative to retain said indication means in said non-tamper state before said indication means is switched to said tamper state by said sensor means, said sensor means being inoperative to switch said indication means to said tamper state before said object is first attached to the body by said fastening means, whereby said indication means will be in said non-tamper state when said object is first fastened to the body of the person to be monitored.
2 Assignments
0 Petitions
Accused Products
Abstract
A personnel monitoring system includes a tag worn by each monitored person. The tag repeatedly emits digital radio signals, and a predetermined bit in the signal changes with time according to a predetermined pattern. Monitoring apparatus detects the radio signals and sends an absence alarm signal if the signals cease. The monitoring apparatus detects spurious, forged signals which do not replicate the predetermined pattern of variation and provides a forgery alarm signal. The tag may be attached to the person by a strap bearing parallel electrical conductors. Attempts to remove the tag by servering the strap cause electrical contact between the conductors. Such contact triggers a detector, which in turn alters the ratio signal.
113 Citations
22 Claims
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1. A personnel monitoring tab comprising:
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(a) an object incorporating means for emitting a signal; (b) fastening means for attaching said object to the body of a person to be monitored; (c) indicative means having an tamper state and a non-tamper state, said indication means being switchable from said non-tamper state to said tamper state, indication means including means for altering said signal while in said tamper state; (d) latch means for retaining said indication means in said tamper state after said indication means is switched into said tamper state; and (e) sensor means for detecting detachment of said object from the body of the person and switching said indication means from said non-tamper state to said tamper state when said object is detached from the body, said latch means being operative to retain said indication means in said non-tamper state before said indication means is switched to said tamper state by said sensor means, said sensor means being inoperative to switch said indication means to said tamper state before said object is first attached to the body by said fastening means, whereby said indication means will be in said non-tamper state when said object is first fastened to the body of the person to be monitored. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A security device comprising an elongated strap and means for detecting severance of said strap, said means for detecting severance including first and second electrical conductors extending generally lengthwise along said strap in proximity to one another, but normally out of contact with one another and means for detecting electrical contact between said first and second conductors, said means for detecting electrical contact between said conductors including means for maintaining said conductors at different potentials so that no current flows through said conductors while said conductors are out of contact with one another and means for detecting current flow in said conductors, whereby said current flow will indicate electrical contact between said conductors.
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18. A personnel monitoring system comprising:
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(a) transmitter means for automatically sending a transmitted signal having a limited range and bearing a plurality of data bits each having a discrete value; (b) fastening means for attaching said transmitter means to a person to be monitored; (c) monitoring means for receiving a signal, recovering data bit values from the received signal, testing the recovered values to determine whether or not the received signal is a valid transmitted signal from said transmitter means, and issuing an indication that said person to be monitored is present in the vicinity of said monitoring means only if a valid signal is received, said plurality of data bits including at least one preselected change bit, said transmitter means including change means for varying the value of each said change bit in said transmitted signal according to a predetermined pattern of variation, said monitoring means including change test means for determining whether the value of each said change bit in the received signal varies according to said predetermined pattern and inhibiting the indication that the monitored person is present if said change bit value does not vary in accordance with said predetermined pattern. - View Dependent Claims (19, 20, 21, 22)
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Specification