Off the top of my head, I'd be suspicious of the HP LJ4L - that's the low end
of the LJ-4 series printers and among it's other many limitations is that
unlike all other LJ-4 series printers, it is not a 600x600 dpi printer. That
leads me to suspect that it also doesn't have the PJL smarts that are an
addition to PCL.  If it cannot understand PJL commands, then it will not
behave properly when sent these commands.  Since HP now hides PCL technical
info, this might be hard to determine via documentation.  Suggestion: swap it
for another printer and connect the other LJ to the same JetDirect External
box with the same cable.

Wayne