PJL

More information about Printer Job Language (PJL) can be found at wikipedia:Printer Job Language.

" Printer Job Language (PJL) is a method developed by Hewlett-Packard for switching printer languages at the job level, and for status readback between the printer and the host computer. PJL adds job level controls, such as printer language switching, job separation, environment, status readback, device attendance and file system commands. While PJL was conceived as an extension to Printer Command Language, it is now supported by most PostScript printers. "