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

EN Device Attendance Commands 8-3
Note This command replaces the lowest priority 00 READY message. If
any higher priority message is displayed (for example, toner low), the
new ready message does not appear until these outstanding
conditions are cleared.
For HP LaserJet 4PJ, 4V, 4MV, 5Si, 5SiMx, and 5Si Mopier printers, if
the LANG variable is set to Japanese, the message is displayed using
the JIS X0201-76 character set.
For the LaserJet 4000, 5000, 8000, and 8100 series printers, if LANG
is set to POLISH, CZECH, or HUNGARIAN, messages are displayed
using the Latin 2 (ISO 8859/2) character set. If LANG is RUSSIAN,
messages are displayed using Cyrillic (ISO 8859/5). For
LANG=TURKISH, the display is in Latin 5 (ISO 8859/9). This is also
true for the HP Color LaserJet 4500 printer, except there is no support
for Turkish or Hungarian on this printer.
Some HP LaserJet printers may have a different limit for the number
of display lines and number of display characters. To request the
display limits, use the INFO CONFIG command. When this command
is used, the printer returns DISPLAY LINES=value and DISPLAY
CHARACTER SIZE=value as part of the response message. For
example, HP LaserJet 4 and 4M printers return DISPLAY LINES=1,
DISPLAY CHARACTER SIZE=16, indicating that the displayed
message is limited to 1 line of 16 characters.
Example: Using the RDYMSG Command
This example simulates a spooler that prints a job from another
application. The spooler uses the RDYMSG command to display the
name of the person printing the job (while the job is printing).
Note In the example below, the @PJL JOB DISPLAY command has been
added to display the job name on the newer printers. (See the note on
page 8-2.)
After the job is printed, the spooler restores the normal ready
message. (The indented command lines indicate those sent by the
printing application; the remaining lines are sent by the spooler.)