Code 39 (also known as USS Code 39, Code 3 of 9) is the first alpha-numeric symbology developed to be used in non-retail environment. It is widely used to code alphanumeric information, such as the model number etc. It is designed to encode 26 upper case letters A-Z, 10 digits 0-9 and 7 special characters - hyphen (-), period (.), dollar sign ($), forward slash (/), plus sign (+), percent (%) as well as the space character.

Although you can put as many characters as you can, in practice you can not encode many characters. Many barcode scanners have a short scan range at 3 inches.

Each Code 39 barcode must begin and end with special bar/space patterns. They are often referred as start/stop character. In the font, the start/stop character is mapped to the asterisk (*). You can also use left square bracket [ and right square bracket ] to produce them.

Creating a Code39 barcode is a simple task. Just enclose your data with asterisks and print the whole string with a C39 font, you get a barcode. For example, let's say that the data to be encoded is:

PN99018

The barcode string for printing as a Code39 barcode would be:

*P99018*

The below escape sequences print the barcode, and the human readable text below the barcode:

(0Y<ESC>(s0p8h12*PN99018*
<ESC>(3@PN99018

C Code

The following code snippet demonstrates the barcode printing in C language.

int PrintPartNumberBarcode(char* pPartNo, FILE* prn)
{
    /*select MRV Code39MA Height 12 points) */
    fprintf(prn, "\x1B(0Y\x1B(s12.00H"); 
    fprintf(prn, "*%s\n", pPartNo);
}

BASIC Code

The following BASIC function returns the same barcode string.

Function GetBarcodeString(partno as string) as String
    Dim str as string
    str = "*" & partno & "*"
    GetBarcodeString=str
End Function