HP PCL/PJL reference - Printer Job Language Technical Reference Manual

EN Programming Tips for Using PJL 11-5
Printer Utilities
Printer utilities are those applications that perform one or more of the
following functions:
• Control printer resources—These programs set printer
features such as the print resolution and number of copies
using the SET, RESET, DEFAULT, and INITIALIZE commands.
• Request information from the printer—Printer status and
feature settings can be requested from the printer using the
ECHO, INFO, INQUIRE, and DINQUIRE commands.
Applications should only use PJL commands that request
status if the application is in direct control of the printer and
there is a bi-directional communication channel between the
printer and the application.
• Monitor the printer status—Device status and timed status
can inform the application of printer events such as printer
open, paper out, or low toner. The USTATUS DEVICE and
USTATUS TIMED commands are used to monitor printer
status. Applications can continuously monitor the printer for
changes in printer state. When the printer changes state, the
application takes appropriate action, such as informing the
user.
In general, the Printer Utilities described here are not used to print
information, but enable the user to request the current printer feature
settings and modify features as desired.