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Two Dimensional Code

IP.com Disclosure Number: IPCOM000097586D
Original Publication Date: 1961-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Nick, HH: AUTHOR

Abstract

Four data tracks A, B, C and D are used in conjunction with four time zones 1,2,3 and 4 to form a four by four two-dimensional data character having sixteen bit positions. Different characters are obtained by a permutation of bits within the four by four bit representation according to the following rules: 1. A character is represented by at least one bit but by no more than four bits. 2. Only one bit can occur in track A, B, C or D. 3. Only one bit can occur in time zone 1, 2, 3 or 4. 4. A bit must always occur in time zone 1 but can be located in any one of the four tracks A, B, C or D. 5. If more than one bit is used, each succeeding bit must occur in consecutive time zones up to a maximum of one bit in each time zone 1, 2, 3 and 4.

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Two Dimensional Code

Four data tracks A, B, C and D are used in conjunction with four time zones 1,2,3 and 4 to form a four by four two-dimensional data character having sixteen bit positions. Different characters are obtained by a permutation of bits within the four by four bit representation according to the following rules: 1. A character is represented by at least one bit but by no

more than four bits.

2. Only one bit can occur in track A, B, C or D.

3. Only one bit can occur in time zone 1, 2, 3 or 4.

4. A bit must always occur in time zone 1 but can be located

in any one of the four tracks A, B, C or D.

5. If more than one bit is used, each succeeding bit must occur

in consecutive time zones up to a maximum of one bit in each

time zone 1, 2, 3 and 4.

With these rules, 64 permutations (characters) are possible with a four by four matrix.

Single error detection and correction are provided by the addition of a fifth time zone and a fifth track. Odd redundancy check bits are provided in the fifth time zone for the respective tracks. The fifth track is provided with even parity bits for the respective time zones. A bit always occurs in the fifth track in time zone 1 because every character always has a bit in this time zone. Thus, five by five bit characters have two dimensional parity which assures single-error correction and double error detection for every character in the code.

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