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FACSIMILE SYSTEM
the DRAM and the MODEM, and between the system controller and the
DRAM to reduce the load placed on the CPU.
The system controller is the IC that controls
converts the serial data that arrives from the reading section to parallel data
and performs chip selection of peripheral ICs, amongst other operations.
2.2
Communications Control Section
This section comprises a MODEM, and is connected to the system control
section by a bus. "MODEM" is an abbreviation of MOdulator/DEModula-
tor. The MODEM on a facsimile performs modulation for transferring the
image data to the telephone line, and demodulation of image data that has
been received. The modulation/demodulation method used complies with
ITU-T
performs transmission of
2.3
Reading Control Section
This section comprises an image processor IC and SRAM for buffering
read data. The image processor IC is connected to the system control sec-
tion via a bus.
After the document has been read by the contact sensor, the resulting
image data undergoes A/D conversion by the image processor IC in the
reading control section and image processing such as resolution conver-
sion in the
sent to the system controller in the system control section.
2.4
Printer Control Section
This section is functionally the same on both an LBP method or a BJ
printer method, though slightly different in some respects. This section
comprises an MPU, system control, DRAM and ROM independent of the
system control section, and handles control of the entire printer. (On an
LBP printer, this section is sometimes integrated as a one-chip microcom-
puter.) The printer control section merely transfers the printer status (status
of printer-related sensors, error status, etc.) to the system control section. It
is provided with an interface for receiving image data for printing, and
communicates with the system control section. Facsimile image data is
converted (resolution conversion, smoothing, etc.) to image data for print-
ing at the system control section.
6–4
recommendations. Among its other functions, the MODEM also
DTMF
horizontal scanning
MPU
peripheral devices. It
signals.
direction, and the resulting image data is
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