HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part II

EN U, Pen Up 20-47
When you use the Symbol Mode (SM) command, PU draws
the specified symbol at each X,Y coordinate. When you use
the polygon mode (PM) command, the X,Y coordinates enter
the polygon buffer (for use when the polygon is edged or
filled).
Coordinates are interpreted in current units: as user-units
when scaling is on; as plotter units when scaling is off.
Whether the PU command uses absolute coordinates or
relative coordinates (increments) depends on the most
recently executed PA or PR command. If you have not issued
a PA or PR command, absolute plotting (PA) is used.
Note If an odd number of coordinates is specified (in other words, an X
coordinate without a corresponding Y coordinate), the printer ignores
the last unmatched coordinate.
Table 20-30
Related Commands Group
PA, Plot Absolute The Vector Group
PD, Pen Down
PE, Polyline Encoded
PR, Plot Relative
SM, Symbol Mode Line and Fill Attributes Group