Re: 3M Security Systems

sgilliam@GUILFORD.EDU
Wed, 7 Jun 2000 11:12:12 -0700 (PDT)

Several years ago a media services technician tested the potential damage
to
magnetic media caused by security gates. He hung a video tape or maybe a
floppy disc on the gate and left it there for a week, and it still worked
perfectly.
I don't know just how scientific this was, but I think the idea is the
energy emitted
by the sensor is just enough to be able to detect a signal, but not enough
to change it.

Maybe our good friend at 3M can explain how this works.!!