HP Color LaserJet 5500 Technical Reference Manual page 105

Note
The permissible environment variables and range of values
for each variable may not be the same in all HP LaserJet
printer models. See Appendix A for a list of valid variables
and the range of values for each variable, or send the INFO
VARIABLES command to request this information directly
from the printer.
Parameters:
The IPARM : port option must be used when setting
port-specific variables. Valid values for port for the HP
LaserJet 4PJ printer are SERIAL and PARALLEL.
variable = value — this parameter sets one of the
environment variables to the specified value. For
example, the @PJL SET RESOLUTION = 600 command
sets the current resolution to 600 dots per inch. See the
table below for all valid variables and values. If you
require a more detailed description of a particular
variable, see the "Environment Variables" section earlier
in this chapter.
Parameter
personality PCL
POSTSCRIPT
port PARALLEL
SERIAL
variable Valid variables for each printer are listed
in Appendix A.
value Appropriate values for each variable are
also listed in Appendix A.
Variable Names
ESCP
Other personalities
may be supported
Supported on
LaserJet 4PJ only
Environment Commands 6-43