115
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 in 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 length 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. Setting 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 (misreads!).
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:
1987
3
Because the data now has an odd length, a leading zero is added, for the final result of :
019873
123456
