“Confidential, Do Not Duplicate without written authorization from NEC.”8-11CIRCUIT DESCRIPTIONGPIO PWB PWC-4649E Circuit OperationThis PWB has two major functions. Firstly, this PWB extends the GPIO (D-Sub 37-pin) connector of the motherboard in the cinema signal processor circuit from the projector interior to the terminal panel located on the sidesurface. Secondly, it distributes the input signal line of the GPIO terminal to the CPU PWB.M9501 on the PWB is an interface used to control the projector with the aid of external equipment or control theexternal equipment from the projector. It is provided with eight input ports and eight output ports. The internalcircuits are designed so that they can be interrupted electrically from the outside by the photo coupler.1. Factors related to the power supply1 The power supply to the PWB is maintained through:POCOPins 12, 13, and 14: +5V for standbyPins 9, 10, and 11: GNDThe POCO connector is connected to the CPU PWB from which the power is distributed.This power supply is connected to the mother board of the cinema signal processor circuit through ConnectorPO6005 on the PWB. It is used to drive the input section of the photo coupler in the cinema interface board.
