The maximum capacity of this supply container/receptacle
expressed in prtMarkerSuppliesSupplyUnit. If this supply
container/receptacle can reliably sense this value, the
value is reported by the printer and is read-only;
otherwise, the value may be written (by a Remote Control
Panel or a Management Application). The value (-1) means
other and specifically indicates that the sub-unit places
no restrictions on this parameter. The value (-2) means
unknown.