Regarding PCL output: The line barcodes (Code39, Code128 and Interleaved 2 of 5) are defined in 600 DPI (Dots Per Inch). If you however stick to an even number of dots, then the barcodes are generated in 300 DPI, which is necessary if you are printing on older printers. If a 600 DPI barcode is sent to a 300 DPI printer, then the barcode will be printed as a black box.
For ZPL/IDP output you define the barcode width with 2 specifications: One for 203 DPI and another for 300 DPI. The size is defined as a specific number of dots in either resolution.
In 203 DPI each dot is 1/203 inches = 0.125 mm.
In 300 DPI each dot is 1/300 inches = 0.0847 mm.
This means, that for label printing you will normally not be able to set the exact same barcode size for 203 DPI as for 300 DPI.
