Circular Interleaved 2 of 5
Circular Interleaved 2 of 5 is a variant of Interleaved 2 of 5 that is typically used for labels for disc-based media standards such as CD, DVD, or Blu-Ray. Circular Interleaved 2 of 5 is often preferred to Circular Code 39 because barcode messages that contain only numbers can be encoded in Circular Interleaved 2 of 5 by using about half the space that is required by Circular Code 39.
Interleaved 2 of 5 is defined in ISO/IEC 16390 Information technology - Automatic identification and data capture techniques - Interleaved 2 of 5 bar code symbology specification.
The symbol comprises the following elements:
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Leading quiet zone
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Start pattern (narrow bar, narrow space, narrow bar, narrow space)
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One or more pairs of symbol characters that represent data (including an optional check digit)
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Stop pattern (wide bar, narrow space, narrow bar)
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Trailing quiet zone
Each Circular Interleaved 2 of 5 character is represented by five elements: five bars or five spaces, two of which are wide and three narrow. The name "Interleaved 2 of 5" comes from the interleaving of the patterns of bars and spaces that represent the individual characters within the symbol: Characters are represented in pairs, and in every 10 elements, the five bars represent one character and the five spaces between them represent the next character.
All Circular Interleaved 2 of 5 barcode messages must contain an even number of digits. Therefore, a leading zero will be added to the front of the barcode message in either of the following situations:
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The character message that is to be encoded contains an odd number of digits and check digits are not in use
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The character message that is to be encoded contains an even number of digits and check digits are in use
Circular Interleaved 2 of 5 contains no intercharacter spaces.
This symbology supports all numeric digits (0-9).
Although this barcode is much more dense than Circular Code 39, the theoretical data security of Circular Interleaved 2 of 5 is not quite as high. For this reason, we suggest that you always use Circular Interleaved 2 of 5 with the optional check digit or that you standardize your barcodes on a single character length.
Circular Interleaved 2 of 5 can contain an optional check digit that is based on the modulo 10 (mod 10) algorithm.
The recommended minimum symbol height for manual scanning is 5.0 mm or 15 percent of the symbol width (excluding quiet zones), whichever is greater. The quiet zones must be at least 10X wide, where "X" is the current X dimension.
The densest Circular Interleaved 2 of 5 barcode that can be printed on an Epson or IBM-compatible dot-matrix printer is about nine characters per inch, not including the start and stop characters. On a laser printer, density can be increased to about 17 characters per inch. (For reading barcodes of this density, we recommend that you use a high-resolution optical scanner.)
Symbol Structure