Code 39

Code 39 is a barcode symbology developed by Intermec in 1969. It is widely used in numerous industries, including libraries and pharmaceuticals. Code 39 is a discrete (the bar(s) encoding one character are contained in a space of specified width) symbology with two different bar widths, a start sequence on its left end and a stop sequence on its right end.

Code 39 can encode uppercase letters (A through Z), digits (0 through 9) and a handful of special characters like the $ sign. The barcode itself does not contain a check digit (in contrast to --for instance-- Code 128). Possibly the most serious drawback of Code 39 is its low data density: It requires more space to encode data in Code 39 than, for example, in Code 128. This means that very small goods cannot be labeled with a Code 39 based barcode. However, Code 39 is still widely used and can be decoded with virtually any barcode reader.