PJL was developed by Hewlett-Packard to provide a method for switching printer languages at the job level, and for status readback between the printer and the host computer. PJL offers application programs an efficient way to remotely control Hewlett-Packard printers. Using PJL, developers can provide applications with the ability to programmatically switch printer languages, monitor printer status, request the printer model and configuration, change control panel default settings, modify control panel messages, and more.

The latest reference manuals can be ordered or downloaded from Hewlett-Packard.