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FACSIMILE SYSTEM
4. OPCNT BOARD
As the operation panel is the part that the user must touch to operate the
facsimile, the OPCNT board in the operation panel is powered ON at all
times to enable use of buttons on the operation panel.
The OPCNT board is configured as follows:
The OPCNT control IC on the OPCNT board performs serial communica-
tions with the system controller on the SCNT board. After this, serial/par-
allel conversion is performed by the system controller, and the signals are
relayed to the MPU.
The following are the main functions of the OPCNT board:
4.1
Detection of Button Input
The OPCNT board detects pressing of the buttons on the operation panel,
and relays this to the SCNT board. Many buttons are provided on the top
surface of the operation panel. If one switch were used for one button,
many input ports would be required for the OPCNT control IC that is con-
nected before the operation panel. For this reason, button input is detected
using a matrix system to prevent an increase in the number of input ports.
The button detection circuit is configured as follows.
6–18
MPU
Parallel bus
controller
SCNT board
Fig. 6-18 Conceptual View of OPCNT Board
• Detection of button input
• LED lighting control
• Display indication control
System
OPCNT
Serial bus
control IC
Keyboard
OPCNT board
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