HP BDPC9 printer memory: The intelligent "Jetmobile BarDIMM Pro" is an extension of the printer firmware and can produce a wide variety of barcodes with dozens of possible variations. The module automatically calculates the (optional) checksums, the "interleaving", and optimizes the length of the Code 128 as well as the start-stop and middle bytes if necessary. The plain text can be printed in four different positions if required. All bar and gap widths (also known as the print ratio or proportion ratio) can be freely defined.