HP Color LaserJet 5500 Technical Reference Manual page 142

Comments:
Unsolicited status allows you to automatically receive
device, job, page, or timed status without requesting it.
Each type of unsolicited status provides different
information and is described on the following pages.
Some printer models may have more (or fewer) types of
unsolicited status than DEVICE, JOB, PAGE, and TIMED.
You can have the printer list the various types of unsolicited
status by issuing the INFO USTATUS command. See
"Example: Using the INFO USTATUS Command" for an
example of this.
Unsolicited status, except for TIMED, can be turned off
individually using the OFF parameter, such as in the
USTATUS JOB=OFF command. TIMED status is turned
off by setting it to zero. Alternatively, all unsolicited device
status can be turned off using the USTATUSOFF command.
DEVICE Variable
The USTATUS DEVICE = value command prompts the
printer to send status messages when device changes occur.
When DEVICE = ON, the printer sends status information
for all changes to printer status. When DEVICE =
VERBOSE, the printer also sends status information for
all PJL parser warnings and errors.
Part of the unsolicited status message sent to the host is a
5-digit code that indicates the status condition. The first 2
digits divide the status codes into different categories. The
general status categories are listed in the following table.
(This is only a general summary of the specified categories.
The full status code listing is located in Appendix D.)
If there is a "DISPLAY=string" portion of the status
message, the string is localized; the same message as that
displayed on the control panel appears in whichever
language is being used.
7-34 Status Readback Commands