The !SETPU() subroutine sets the characteristics of a print unit.
CALL !SETPU(key, unit, value, status)
The !SETPU() subroutine sets the print unit characteristic specified by key to the given value. It is closely related to the SETPU statement.
CALL !SETPU(PU$LOCATION, 3, "LASER", STATUS)
The above statement sets the destination for print unit 3 to be the LASER printer.