Electronic fiber optic seal monitors
First Claim
1. A method of sealing a container comprising:
- connecting the fiber optic cable to the container,connecting a light source to a first end of the cable,connecting a photodetector to a second end of the cable,reading dark output of the photodetector,pulsing the light source,reading light output of the photodetector,storing the dark output and the light output in memory,comparing, at intervals, current dark output of the photodetector with stored dark output,pulsing the light source,comparing light output of the photodetector with stored light output of the photodetector, andreporting results of the comparing.
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Accused Products
Abstract
The new seal monitor uses of a time dependant pseudo random number or a number from a time pad, which are lists of random numbers often used in encryption. This number changes periodically, for example, once an hour or whatever time interval is deemed timely by the particular application. It is intended that a remote monitoring station would send a request to the monitor and the monitor would respond with the random number that dependant on the time the monitor was started and how much time has elapsed. If the random number returned is correct it infers that the monitor is operating correctly and the seal has not been tampered with. If the monitor does not respond or responds with an incorrect number then the monitor or the seal has been tampered with. Light through a cable is periodically compared with historic outputs from that cable.
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Citations
15 Claims
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1. A method of sealing a container comprising:
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connecting the fiber optic cable to the container, connecting a light source to a first end of the cable, connecting a photodetector to a second end of the cable, reading dark output of the photodetector, pulsing the light source, reading light output of the photodetector, storing the dark output and the light output in memory, comparing, at intervals, current dark output of the photodetector with stored dark output, pulsing the light source, comparing light output of the photodetector with stored light output of the photodetector, and reporting results of the comparing. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A container sealing method comprising:
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securing a container with a light transmitting seal, monitoring the seal by pulsing light through the seal, reading light output from the seal, generating random numbers from a time pad, remotely requesting the monitoring, responding to the requesting with a generated random number according to time when the seal is intact, and failing to respond or responding with an incorrect number when the seal has been tampered with. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A monitor for optical fiber cables comprising:
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optical fibers having first and second ends, an LED connect to the first ends of fibers, a detector connected to the second ends of the fibers, a timer connected to the LED and to the detector, an amplifier connected to the detector, an analog-to-digital converter connected to the amplifier, a memory connected to the converter, a comparator connected to the memory and to the converter for comparing present outputs with past outputs in the memory, a clock connected to the comparator, to the LED, and to the detector for keying the LED, the detector and the comparator, and a variable code source connected to the comparator and to the clock for outputting a time dependent code upon an agreement of outputs in the comparator. - View Dependent Claims (14)
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15. A method of sealing a container comprising inserting a cable end, starting a clock, transmitting time and code, detecting dark light, storing dark light, detecting LED light, storing LED light, receiving poll, starting a timer, detect dark light, comparing detected dark light with stored dark light, lighting LED, detecting lighted light, comparing lighted light with the stored lighted light, when the dark lights and the lighted lights match, outputting a time dependent output code, and when either lights do not match outputting time, no output, or an alarm.
Specification