Introduction to barcode type Codabar

Codabar, also known as Codeabar, is a linear barcode symbology that is commonly used in libraries, blood banks, overnight package delivery services, and some other specialized applications. It was developed in 1972 by Pitney Bowes, Inc. for its "Matrix Barcode" readers and later standardized by the AIM (Automatic Identification Manufacturers) International.

Codabar is a self-checking barcode, which means that each character includes start and stop symbols that enable basic error detection without requiring a checksum digit. It can encode numeric digits (0-9), six special characters (- $ : / . +), and four letters (A, B, C, D). The barcode can vary in length and doesn't include alphanumeric characters like many other barcode types.

Each character in Codabar is represented by a series of four bars and three spaces. The start and stop characters are represented by unique combinations of these bars and spaces. The barcode is considered one of the simpler types, which makes it easy to print and read using both laser scanners and traditional handheld wands.

Here's an example of the start and stop characters, along with their corresponding characters:

- A: 101010011
- B: 101011001
- C: 101001011
- D: 110010101

For example, to encode the number 123 in Codabar, the barcode representation would be: B-A-A-B-B-C-C-A-A-B-B-D

Please note that while Codabar is still used in some niche applications, more modern and efficient barcode types like Code 128 and QR codes have largely replaced it in most industries due to their ability to store more information and offer error correction capabilities.