Hewlett-Packard was one of the first companies to produce a laser printer for PCs, and most software products include drivers for HP printers. The drivers control the printers through a language called PCL (printer control language ). Other manufacturers of laser printers design their printers so that they, too, understand PCL, making them able to emulate HP printers. In this way, their printers are HP-compatible and are thus automatically supported by many software products.
No non-HP printer, however, is 100 percent HP-compatible. Manufacturers claim HP compatibility even if their printers only recognize a subset of PCL commands. Note also that there are different versions of PCL. A printer may be able to emulate an HP LaserJet Plus but not a LaserJet II. Finally, HP laser printers support font cartridges, and not all HP-compatible printers can accept the same cartridges.