Oki OKIFAX 5950, Maintenance Manual

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SIGNAL FLOW
OF5750/5950 Series January 2001 A2 - 21
A2.2 Explanation of Signal Flowchart
(1) Copy Mode
The analog data output from the image sensor is input to the MCNT-PCB to be amplified
by the amplifier. The amplified analog data is input to the scanner controller. Next, the
analog data is converted to digital data by the built-in A/D converter. The digital data is
corrected by the internal correction function, transferring binary-coded data to the IOGA5
every eighth pixel. The data input to the IOGA5 is temporarily written into the external
DRAM (4 megabits x 16 bits). The written data is sent, through the IOGA5, to the LED
head in sync with the print operation.
(2) G3 Send Mode (MH/MR/MMR Codes)
The analog data output from the image sensor is input to the MCNT-PCB to be amplified
by the amplifier. The amplified analog data is input to the scanner controller. Next, the
analog data is converted to digital data by the built-in A/D converter. The digital data is
corrected by the internal correction function, transferring binary-coded data to the IOGA5
every eighth pixel. The data input to the IOGA5 is temporarily written into the external
DRAM (4 megabits x 16 bits). The written data is converted to MH/MR/MMR codes by
firmware, then written into the external DRAM again.
The converted data is sent to the modem board to be modulated. The data modulated by
the modem is sent to the NCU board by the Send signal “S.” The data sent to the NCU
board is amplified there, then output to the public line.
(3) G3 Receive Mode (MH/MR/MMR Codes)
The signal input from the public line to the NCU board is amplified, input to the modem
board as an R signal, demodulated by the modem, and written into the DRAM on the
MCNT PCB.
MH/MR/MMR-code data is converted to image data by firmware and written into the
DRAM again. The written data is sent, through the IOGA5, to the LED head in sync with
the print operation.
(4) G3 Receive Mode (JBIG Code)
The signal input from the public line to the NCU board is amplified, input to the modem
board as an R signal, demodulated by the modem, and written into the DRAM on the
MCNT PCB.
JBIG-code data is sent to the JBIG control LSI chip to be converted to image data. Then,
the image data is written into the DRAM.
The written data is sent, through the IOGA5, to the LED head in sync with the print
operation.
(5) G3 Send Mode (JBIG Code)
The analog data output from the image sensor is input to the MCNT-PCB to be amplified
by the amplifier. The amplified analog data is input to the scanner controller. Next, the
analog data is converted to digital data by the built-in A/D converter. The digital data is
corrected by the internal correction function, transferring binary-coded data to the IOGA5
every eighth pixel. The data input to the IOGA5 is temporarily written into the external
DRAM (4 megabits x 16 bits). The written data is converted to MH/MR/MMR codes by
firmware, then written into the external DRAM again.
The converted data is sent to the JBIG control LSI chip to be converted to JBIG codes.
Next, the JBIG-code data is sent to the modem board to be modulated. The data modu-
lated by the modem is sent to the NCU board by the Send signal “S.” The data sent to
the NCU board is amplified there, then output to the public line.