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Method and system for storing, retrieving, and managing data for tags

  • US 9,460,233 B2
  • Filed: 09/27/2013
  • Issued: 10/04/2016
  • Est. Priority Date: 10/30/2003
  • Status: Active Grant
First Claim
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1. A method for maintaining proximity of one or more tags comprising:

  • receiving a first message on a tag that includes a tag audible alarm, that is broadcast at a regular time interval from a partner tag that includes a partner tag audible alarm using a partner timer interrupt on the partner tag, and that includes a partner identifier of the partner tag that is used to distinguish the partner tag from other tags and a first broadcast time that is the time the first message is broadcast from the partner tag;

    reading the partner identifier and the first broadcast time of the partner tag from said first message on the tag;

    resetting tag alarm counter on the tag for said read partner identifier at the same regular time interval using a timer interrupt on the tag only if the first broadcast time in the first message is within a predetermined time period in order to prevent a replay attack;

    broadcasting from the tag a second message that includes an identifier of the tag and a second broadcast time that is the time the second message is broadcast from the tag at the same regular time interval using the timer interrupt on the tag that the partner tag receives and uses to reset a partner tag alarm counter on the partner tag only if the second broadcast time in the second message is within the predetermined time period in order to prevent a replay attack;

    sounding an alarm on the tag audible alarm of the tag when the tag alarm counter exceeds the regular time interval before the tag receives a third message from the partner tag; and

    sounding an alarm on the partner tag audible alarm of the partner tag when the partner tag alarm counter exceeds the regular time interval before the partner tag receives a fourth message from the tag.

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