“Confidential, Do Not Duplicate without written authorization from NEC.”
8-11
CIRCUIT DESCRIPTION
GPIO PWB PWC-4649E Circuit Operation
This PWB has two major functions. Firstly, this PWB extends the GPIO (D-Sub 37-pin) connector of the mother
board in the cinema signal processor circuit from the projector interior to the terminal panel located on the side
surface. 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 the
external equipment from the projector. It is provided with eight input ports and eight output ports. The internal
circuits are designed so that they can be interrupted electrically from the outside by the photo coupler.
1. Factors related to the power supply
1 The power supply to the PWB is maintained through:
POCO
Pins 12, 13, and 14: +5V for standby
Pins 9, 10, and 11: GND
The 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 Connector
PO6005 on the PWB. It is used to drive the input section of the photo coupler in the cinema interface board.
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