About Codabar Barcodes
Codabar (also known as Ames Code, NW-7, or USD-4) is a linear, self-checking 1D barcode symbology developed in 1972 by Monarch Marking Systems. It was designed to be easily read by early scanning technology, even when printed on low-quality paper or hand-written using specialized equipment. Codabar is a discrete barcode, meaning the spaces between characters are not part of the data. It is primarily used in specialized environments that require numeric encoding with flexible start and stop options.
How Codabar Encoding Works
Codabar encodes 16 basic characters, including the numeric digits 0-9 and six symbols (-, $, :, /, ., +). It requires one of four start and stop characters: A, B, C, or D (represented as lowercase a-d in some software). These start/stop letters allow the barcode to convey supplementary information, such as the classification of an item. Because Codabar is self-checking, it does not require an official check digit, though a checksum can be added for high-security applications.
Common Applications and Industries
Codabar is historically prominent in U.S. blood banks, photo processing labs, library catalog systems, and overnight courier packaging. In blood banks, the start/stop characters designate donor types and product categories. While modern logistics systems have largely transitioned to Code 128, Codabar remains active in legacy database architectures and library book checkouts due to its simplicity and reliable read rates on aged labels.
Advantages & Limitations
Codabar is highly tolerant of poor print quality and can be read by older, low-resolution optical scanners. It is self-checking and supports four different start and stop characters for basic categorization. The major drawback is its extremely limited character set (numeric and six symbols only) and low data density, which makes it wider and less efficient than modern symbologies like Code 128.