Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!csc.anu.oz.au!csis!skravis
From: skravis@csis.dit.csiro.au (Simon Kravis)
Newsgroups: sci.electronics
Subject: Stock control tags
Message-ID: <1990Oct12.044801.8842@csis.dit.csiro.au>
Date: 12 Oct 90 04:48:01 GMT
Organization: csis.dit.csiro.au
Lines: 5

Does anyone know how the detection system for the metallic tags attached to
CDs and other small and valuable items in shops works? It looks as though it's
some kind of magnetic detection system, judging by the large sensing coils
near the door and the fact the the tags are deactivated by running what looks
like a magnetic roller over them.