Returns a number that indicates how full the input tray
is. If the device can only detect empty / not empty the
device returns -1 for not empty and 0 for empty. If the
device can determine how full the tray is, the device
returns a percentage full from 0% to 100%
Additional information:
LaserJet 4V can only detect empty/not empty tray.
It returns -1 for not empty and 0 for empty.