Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!think!husc6!psuvax1!psuvm!cunyvm!ndsuvm1.bitnet!nu013809
From: NU013809@NDSUVM1.BITNET (Greg Wettstein)
Newsgroups: comp.sys.ibm.pc
Subject: Magnetic encoding on cards.
Message-ID: <2549NU013809@NDSUVM1>
Date: 17 Jul 89 15:51:46 GMT
Organization: North Dakota Higher Education Computer Network, Fargo, ND
Lines: 43
Disclaimer: Author bears full responsibility for contents of this article.

I am interested in locating any information regarding technical aspects of
the encoding methods used to place information on the magnetic strips commonly
found on bank cards or credit cards.  As a preface to this I should probably
say that I am not interested in counterfeiting (sp?) or modifying bank cards or
credit cards, hopefully this will put everyone's mind at ease. -).

The project that I am involved with requires that we give individuals some
method of carrying electronically stored information.  I of course suggested
3.5 micro-floppies but these were deemed excessively bulky.  The project
administrators would like to be able to store the information on something
approximating the size of a credit card.  The administrators know about the
magnetic strips on such cards and are wondering how much information can be
stored on one or more of these strips.

My questions (problems) are as follows:

   1.) What density can these strips be encoded at.  I have a sneaky hunch that
       something like 6250 bpi is probably out of the question.

   2.) Is it possible to re-record (edit) the information that is encoded on
       these cards.  The administrators envision a system where the information
       carried on each card would be dynamic and therefore would require
       modification or additions of data.

   3.) What type of hardware is available for reading this information and is
       possible to interface this hardware to a personal computer which would
       serve as the user interface.

   4.) What data integrity questions must be addressed?  I look at the back of
       my credit cards and I notice a lot of gouges through the magnetic strip,
       how does such physical trauma affect data retention and recording
       densities?

Any information provided by the net would be greatly appreciated.  We will be
needing some hardware vendors if this project proceeds so I would be interested
in hearing from anyone who works for companies involved with this type of
technology.  Replies either via the net or e-mail would be greatly appreciated.
I will summarize all responses if sufficient interest is show by others.  Once
again thanks in advance for whatever help may be extended.

                                          As always,
                                          G.W. Wettstein
                                          NU013809@NDSUVM1