Canon MultiPASS C755 Service Manual - Page 137

c-1 System controller IC IC 301, b-1 Modem IC IC 701

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MultiPASS C755 Chapter 3: Maintenance & Service a-4) Main ROM (IC201) This 8 Mbit ROM contains the control programs (e.g. operation panel, scanner and communications section etc.) for this fax. a-5) SRAM (IC 202) This 256 Kbit SRAM is backed up by lithium battery. SRAM holds data registered for system control and communications management information. Also, SRAM stores contact sensor LED light-on time data. a-6) DRAM (IC 203) This 64Mbit DRAM is used as memory for storing image data, and as an MPU work area. a-7) USB Controller (IC 901) USB interface control function. b) Communication control section (on Modem board) b-1) Modem IC (IC 701) A Conexant FM336 (PLCC type) is used as the modem IC. The MODEM IC carries out G3 modulation conforming to ITU-T standards V.34, V.29, V.27ter, V.21, V.17 and V.8 on transmitted data received from the MPU during transmission. During reception, the MODEM IC carries out G3 modulation on received signals from the telephone line, according to the same standards. c) Document scanning section c-1) System controller IC (IC 301) The system controller IC include image processing function (UHQ) are as follows: • A/D conversion Input signals from the contact sensor are A/D converted. • Generation of shading data (RGB color & Black and white) • ABC (Auto Background Control) Sets the slice level for each scan line. • Edge enhancement processing • Binaryzation processing • Halftone processing • Contact sensor LED control • Document feed motor control Also, the system controller IC include color image processing function are as follows: • Color image processing The RGB data is converted into CMYK print data. 3-86

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3-86
MultiPASS C755
Chapter 3: Maintenance & Service
a-4) Main ROM (IC201)
This 8 Mbit ROM contains the control programs (e.g. operation panel, scanner and communications
section etc.) for this fax.
a-5) SRAM (IC 202)
This 256 Kbit SRAM is backed up by lithium battery.
SRAM holds data registered for system control
and communications management information.
Also, SRAM stores contact sensor LED light-on time
data.
a-6) DRAM (IC 203)
This 64Mbit DRAM is used as memory for storing image data, and as an MPU work area.
a-7) USB Controller (IC 901)
USB interface control function.
b) Communication control section (on Modem board)
b-1) Modem IC (IC 701)
A Conexant FM336 (PLCC type) is used as the modem IC. The MODEM IC carries out G3 modulation
conforming to ITU-T standards V.34, V.29, V.27ter, V.21, V.17 and V.8 on transmitted data received
from the MPU during transmission.
During reception, the MODEM IC carries out G3 modulation on
received signals from the telephone line, according to the same standards.
c) Document scanning section
c-1) System controller IC (IC 301)
The system controller IC include image processing function (UHQ) are as follows:
•
A/D conversion
Input signals from the contact sensor are A/D converted.
•
Generation of shading data (RGB color & Black and white)
•
ABC (Auto Background Control)
Sets the slice level for each scan line.
•
Edge enhancement processing
•
Binaryzation processing
•
Halftone processing
•
Contact sensor LED control
•
Document feed motor control
Also, the system controller IC include color image processing function are as follows:
•
Color image processing
The RGB data is converted into CMYK print data.