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

EN Status Readback Commands 7-31
USTATUS Command
The USTATUS command is used to enable or disable unsolicited
printer status. Unlike the status information solicited by sending the
INQUIRE, DINQUIRE, or INFO commands, unsolicited status is sent
automatically when the status changes. Use the USTATUS command
when you want to know:
Device status changes (such as printer open, paper jams, and
paper out conditions)
Job status changes (when a JOB command is encountered,
the job completely prints, or the job is canceled)
Page status changes (when each printed page reaches the
output tray)
Timed status (periodic status report at a specified time
interval)
Note Unlike solicited status, the USTATUS command does not have an
immediate response. Instead, unsolicited status messages are sent
only when the printer status changes.
Syntax:
@PJL USTATUS variable = value [<CR>]<LF>
Status Message Syntax:
@PJL USTATUS variable <CR><LF>
[1 or more lines of printable characters or <WS>
followed by <CR><LF>]
<FF>