Description: The current capacity of the input sub-unit in input sub-unit capacity units (PrtCapacityUnitTC). If this input sub-unit can reliably sense this value, the value is sensed by the printer and may not be changed by management requests; otherwise, the value may be written (by a Remote Contol 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. The value (-3) means that the printer knows that at least one unit remains. Refer to Internet Draft Printer MIB, expiring Sept. 1997 for more details. Additional information: The Laserjet 1220 products can only detect empty/not empty in its trays. It returns -3 for not empty and -2 (unknown) for any other condition (e.g. tray is empty or tray is removed).