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

17-12 An Introduction to HP-GL/2 Vector Graphics EN
Notes When LOST mode is entered, the pen is raised and the following
commands are ignored: AA, AR, AT, CI, CP, EA, ER, EW, LB, PE, PM,
PR, RA, RR, RT, and WG.
The commands allowed in LOST mode are: AC, AD, CF, CO, DF, DI,
DR, DT, DV, ES, FT, IN, IP, IR, IW, LA, LO, LT, PA, PD, PG, PU, PW,
RF, RO, RP, SA, SB, SC, SD, SI, SL, SM, SP, SR, SS, TD, UL, WU,
and the PM1/PM2 forms of PM.
The commands IN, PG, RP, and PA, with in-range parameters, clear
LOST mode, PD and PU in absolute plotting mode, with in-range
parameters, also clear LOST mode. When PD clears LOST mode, a
line is drawn from the last valid current position to the first point in the
PD parameter sequence. If PA clears LOST mode, the pen will not go
down until a PD command is received.