Browse Prior Art Database

Zero Insertion in Magnetic Stripe Encoding

IP.com Disclosure Number: IPCOM000049056D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Shovelin, J: AUTHOR

Abstract

In magnetic stripe encoding it is normal to use 4-bit character coding giving 16 unique characters. However, two particular characters, X'B' and X'F', are reserved as codes for the start of record and end of record and are not available for use to code data.

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Zero Insertion in Magnetic Stripe Encoding

In magnetic stripe encoding it is normal to use 4-bit character coding giving 16 unique characters. However, two particular characters, X'B' and X'F', are reserved as codes for the start of record and end of record and are not available for use to code data.

By treating the data section of the magnetic stripe as a bit stream and using zero insertion when the stripe is encoded and zero deletion when the stripe is read, X'B' and X'F' can be used in the data section as well as for start and end of record codes.

Since X'B' equals B'1011 and X'F' equals B'1111, the rule for encoding is to insert a zero after any bit sequence 101 or 111. For decoding, the rule is to delete the next zero after any bit sequence 101 or 111.

This technique increases the number of code points available to the user by
12.5 percent.

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