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Bidirectional Magnetic Stripe Reader

IP.com Disclosure Number: IPCOM000088581D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Mason, ML: AUTHOR

Abstract

The original IBM magnetic stripe card reader reads cards only as they are inserted. When the card is inserted in the reader a microswitch is picked which turns "on" the amplifier card so data can be read. A second microswitch is picked when the card is completely inserted which turns "off" the amplifier card. The amplifier card will not be turned "on" until another card is inserted.

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This is the abbreviated version, containing approximately 82% of the total text.

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Bidirectional Magnetic Stripe Reader

The original IBM magnetic stripe card reader reads cards only as they are inserted. When the card is inserted in the reader a microswitch is picked which turns "on" the amplifier card so data can be read. A second microswitch is picked when the card is completely inserted which turns "off" the amplifier card. The amplifier card will not be turned "on" until another card is inserted.

By reversing the connecting wires to the microswitches, the amplifier card is read on withdrawal only. By disconnecting the switches and jumpering the connecting wires so that the amplifier is "on" all of the time, the card will be read when inserted and again when withdrawn.

The software support for the forward read is modified so that data being read will not require a START OF MESSAGE (SOM) character at the beginning of the message. If the SOM character does precede the message, data is being read when the badge is being inserted. If not, a withdrawal read is assumed. If the data is being read in withdrawal mode, a mirror image is created in the computer and the forward read processing code is used to check the data. The message read will be presented to the application program in exactly the same format no matter what direction it is read. In other words, the application program would have no way of knowing whether the badge was read when inserted or withdrawn.

The withdrawal reading capability makes it feasible to install magnetic stripe reade...