Code 39 is one of the most widely and commonly used barcode types. It is a linear or 1d barcode and is also known as USS code 39, code 3 of 9, Alpha 39, USD-3, and Type 39. Code 39 is capable of encoding all the alphanumeric characters (26 Alphabets and 10 numeric characters ranging from 0 to 9). It can also encode space and six special characters including the dollar sign ($), Period (.), minus (-), percent (%), slash (/), plus (+). Asterisk (*) can also be used but only at the start or end of the code.
Code 39 was initially designed by two researchers from Intermec, named Ray Stevens and Dr.David Allais in the year 1974. Initial code 39 was created with two wide black bars and a wide space which could encode 40 characters excluding the first or last symbol resulting in 39 total characters. It is for this reason that this barcode is called code 39. The latest code 39 contains 9 bars in total with three wide and six narrow bars.
Code 39 has been recognized by ANSI (American National Standards Institute) as MH10.8M-1983. It is general purpose and most widely used barcode type. Its basic purpose is to encode a small amount of information containing alphabets as well as numeric characters in a linear pattern of bars and spaces.
Code 39 barcode should be used when a small amount of information needs to be encoded.