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Appendix H:

Interleaved 2 of 5 Code

Interleaved 2 of 5 Code is a numeric-only, even-number-of-digits bar code. It is widely used in warehouse and industrial applications.
A combination of five elements, two wide and three narrow represent each character. Odd-number position digits are
encoded in the bars, even -number positions i n the spaces. Interleaved 2 of 5 Code is so susceptible to partial scans
being interpreted as valid reads that we recommend only one length of I 2 of 5 to be read. Using one lengt h of data
allows the TriCoder to ignore any valid partial reads. As shipped, the TriCoder is set to look for a 6 digit I 2 of 5 code,
but you can set the length to something different using the TriCoder Setup Menu. Settin g the length to 00 digits allows
variable length bar codes scanning. If you must use the 00 setting, you must use the “Minimum/Maximum” data length field when
creating a program in the TriCoder to check each field for the proper length; otherwise, expect partial (bad data!) reads (mi sreads!).
A Mod 10 Check Digit is optionally available for use with I 2 of 5. The exact check digit calculation is illustrated below.

Interleaved 2 of 5 Mod 10 check digit calculation

Assume that the bar code data is 1987.
Starting with the least significant digit (in this case, a 7), label the digits alternatively even and odd.
7 - even
8 - odd
9 - even
1 – odd
Take the sum of the odd digits: 8 + 1 = 9
Multiply the sum of the even digits by 3: (7 + 9) x 3 = 48
Add the results of steps 3 and 4: 9 + 48 = 57
Subtract the result of step 5 from the next highest multiple of 10:
60 - 57 = 3
The checksum becomes the low-order digit: 19873
Because the data now has an odd length, a leading zero is added, for the final result of : 019873
123456