HP 5100tn Printer Job Language - Technical Reference Manual - Page 185

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. Programming Tips 10-5