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Method and system for remote monitoring and tracking of inventory

  • US 5,887,176 A
  • Filed: 06/28/1996
  • Issued: 03/23/1999
  • Est. Priority Date: 06/28/1996
  • Status: Expired due to Fees
First Claim
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1. A system for remotely monitoring and tracking a plurality of units of inventory, comprising:

  • a plurality of transponders each fixedly mounted onto a corresponding unit of inventory;

    at least one interrogator located remotely from said plurality of transponders, said interrogator having means for conducting two-way communication with each of said transponders, and each of said plurality of transponders having means for conducting two-way communication with said interrogator; and

    means for controlling operation of said interrogator whereby said interrogator controls operation of each of said plurality of transponders, whereinsaid interrogator includes means for periodically transmitting an interrogation signal to each of said plurality of transponders,each of said plurality of transponders includes means for controlling operation of said transponder between one of a fully active state and a minimal power conserving state, and means for monitoring for the presence of interrogation signals from said interrogator during said minimal power conserving state, and means for processing said interrogation signal and transmitting data signals to said interrogator in response to said interrogation signal in said fully active state, said data signals including data on at least one of a status, content, and description of said unit of inventory to which a corresponding one of said plurality of transponders is attached,said means for monitoring for the presence of interrogation signals includes a transceiver circuit having a signal receiving mode of operation for receiving said interrogation signals during said minimal power conserving state, andsaid means for controlling operation of said transponder includes a first timer circuit for timing when to alternatingly energize and de-energize said transceiver circuit into and out of the signal receiving mode, respectively, during said minimal power conserving state.

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