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

EN Device Attendance Commands 8-5
OPMSG Command
The OPMSG command prompts the printer to display the specified
message and go offline. Use this command to display a message and
halt printing until the operator presses the On Line, Continue, or
Reset key.
Syntax:
@PJL OPMSG DISPLAY = "message" [<CR>]<LF>
Parameters:
DISPLAY = "message" — The variable message can be any
combination of printable characters (except quotation marks,
character 34) and spaces or horizontal tab characters, with a
limit of 1 line of 16 characters (see “Comments” below). The
message variable is a string and must be enclosed in
quotation marks as shown in the command syntax.
Comments:
On some HP printers, the first two display characters blink. To avoid
blinking, begin the message with two blank spaces.
Some HP LaserJet printers may have a different limit for the number
of display lines and number of display characters. To request the
display limitations, use the INFO CONFIG command. The printer
returns DISPLAY LINES=value and DISPLAY CHARACTER
SIZE=value as part of the response message. For example, the 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.
Parameter Functional Range Default
DISPLAY = "message" Roman-8 characters 33 and
35 – 255, <SP>,<HT>
N/A