Codabar is a self-checking barcode that is designed to be read on printed forms, especially from dot matrix printers. Its typical uses have include Fed-Ex packages and blood bank forms. In many ways, the Codabar code has become outdated, as newer code forms now allow a much larger amount of information to be contained in a much smaller space. However, the Codabar is not yet obsolete, and is still in use in libraries (on the spines of books) and several other organizations.
Specifications: A Codabar barcode consists of up to 16 different numeric characters, plus an optional 4 more letter characters (generally A, B, C, and D), which are used to designate the beginning and the end of the code. The order the letters are placed in designates what the barcode is being used for: library, blood bank, photo lab, etc. Since Codabar is self-checking, a check number at the end is not necessary, though some organizations choose to employ one anyway.
Advantages: Codabar is large and clearly spaced, making it easy to scan, even when printed by a standard printer. The code is also self-checking, which eliminates errors in entering in the code.
Disadvantages: As previously mentioned, Codabar is quickly going out of style, and being replaced by other, more efficient product identifiers.