Circular Interleaved 2-of-5

The Circular Interleaved 2-of-5 character set only contains the ten digits, 0-9. However, if you only need to encode numbers, Circular Interleaved 2-of-5 does the job in about half the space of Circular Code 39. Although much denser 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 Circular Interleaved 2-of-5 always be used with the Check Digit option enabled or that you standardize on a single character length of Circular Interleaved 2-of-5 barcodes.

The densest Circular Interleaved 2-of-5 barcodes that can be printed on an Epson or IBM-compatible dot-matrix printer is about 9 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 use of a high-resolution optical scanner.)

Each Circular Interleaved 2-of-5 character is represented by five elements: five bars or five spaces. Like Circular Code 39, the name Circular Interleaved 2-of-5 comes from the patterns of bars and spaces that represent the individual characters within the barcode. Each character has two wide and three narrow elements. With Circular Interleaved 2-of-5, characters are represented in pairs. In each 10 elements, the five bars represent one character and the five spaces in 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 Interleaved 2-of-5 barcode message in either of the following two situations:

• If the character message to be encoded contains an odd number of digits and check digits are not in use.

• If the character message to be encoded contains an even number of digits and check digits are in use.

Unlike Circular Code 39, Circular Interleaved 2-of-5 contains no intercharacter spaces. However, Interleaved 2-of-5 does have start and stop characters.

Unlike the Circular Code 39 asterisk which is used as the start and stop character at each end of the barcode, the Circular Interleaved 2-of-5 start and stop characters are different from each other. They are also shorter than the standard character length in the symbology and no particular character (like the asterisk in Circular Code 39) is associated with them.

From left to right, the start character is:

narrow bar

narrow space

narrow bar

narrow space

From left to right, the stop character is:

fat bar

narrow space

narrow bar