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Code 2 of 5 Interleaved
Code 128
Code 3 of 9

Bar code specifications

Interleaved 2 of 5

Solutions available: Windows stand-alone font, Windows font + encoder, AFP, Xerox, PCL, and bespoke solutions.

Please email sales@terrapin.co.uk with your requirements and we will find a solution for you.

Interleaved 2 of 5 specification
Data Type: Numeric (even number of digits only)
Bar Code Length: Variable
Checksum: Optional
Wide/Narrow bar width ratio: 2.4:1 - 3:1 (where 3:1 is the optimum ratio)

Interleaved 2 of 5 is a high-density bar code for encoding numeric-only data. The symbol length is variable and can be as long as necessary to store the encoded data.

The character set consists of 100 pairs of digits from 00 99, and a start and stop character.

Interleaved 2 of 5 can only be used for encoding an even number of digits. If you have an odd number of digits, you should insert a '0' at the beginning of the string.

The bar code is called 'interleaved' because the first digit is encoded in the bars and the second digit is encoded in the spaces. Each digit consists of 5 elements (two wide and three narrow ones) and is self-checking.

The complete bar code symbol consists of a quiet zone, the start character, the data string, and a trailing quiet zone. A check digit is optional and should be inserted before the stop character.

Encoding the symbol

Example data 1234567890

The 10 individual numbers in the example must be turned into pairs of digits and converted to character positions in the bar code font. This is done by referencing the appropriate character arrangement table.

For fonts supplied in TrueType or Type 1 format, a rule can be followed rather than the Windows Character Arrangement Table. This rule is that for pairs of digits 00 93, add 33 to the digit pair to determine the character position. For pairs of digits 94 and over, add 103 to the pair. For fonts in Xerox or AFP format, the appropriate character arrangement table must be utlised.

Data Start 12 34 56 78 90 Stop
Character position in font 203 44 66 88 110 122 204
Keystroke Ë , B X n z Ì

The final string should look like this:
start character Ë data ,BXnz stop character Ì

Check Digit
A check digit can be used to mathematically verify that the bar code data is correct. With Interleaved 2 of 5 the check digit is optional, but if desired a Modulo 10 with weighting of 3, 1, 3 is used. The string must always be an even number of characters, so if the addition of a check digit gives an odd number, a zero should be added to the beginning of the string.

Note: the check digit is designated as Modulo 10, but is in fact a surplus to the number 10. Mathematically speaking, Modulo 10 is the remainder of the sum when the total is divided by 10.

Beginning with the left-most digit in the string, alternately multiply each number by 3 then 1 then 3 etc.

Data digit sequence 1 2 3 4 5 6 7 8 9 0

Weighting factor (multiply) 3 1 3 1 3 1 3 1 3 1

Total 3 2 9 4 15 6 21 8 27 0 = 95

The check digit is the digit needed to be added to the sum to make it an even multiple of 10. In this case the check digit is 5.

START 0 1 2 3 4 5 6 7 8 9 0 5 STOP

Modulo 10 (Weighting 3)

Character Arrangement Tables

  • Windows format
  • IBM AFP Format (and Windows for both platforms)
  • Xerox Format