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From: jra@lawday.Dayton.NCR.COM (John.Ackermann@Dayton.NCR.COM)
Newsgroups: sci.electronics
Subject: Re: Wiegand wires?
Message-ID: <480@lawday.Dayton.NCR.COM>
Date: 27 Sep 90 14:44:26 GMT
References: <5770030@hpscdc.scd.hp.com> <10960034@hpldola.HP.COM>
Reply-To: jra@lawday.UUCP (John.Ackermann@Dayton.NCR.COM)
Organization: NCR Corporation, Dayton, Ohio
Lines: 14

In article <10960034@hpldola.HP.COM> paul@hpldola.HP.COM (Paul Bame) writes:
>Speaking of credit cards, why don't we use bar codes or some other optical
>method rather than magnetic?  Seems like it would be more reliable.
>
ATM cards use a magnetic stripe because the machines actually write transaction
info on on the stripe.  ATMs do this so that you can't go from machine to
machine (some of which may not be online to your bank) and withdraw in excess 
of your limit.  Each transaction decrements the daily limit value stored
on the stripe. 
-- 
John R. Ackermann, Jr.						 (513) 445-2966
Law Department, NCR Corporation			     	     VoicePlus 622-2966
Dayton, Ohio					  John.Ackermann@Dayton.NCR.COM
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