Canon iR1600 Series, Руководство по обслуживанию

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COPYRIGHT © 2002 CANON INC. CANON FAX BOARD REV.0 MAR. 2002
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CHAPTER 2 BASIC OPERATION
1.2 Functions
a. Image Processor PCB
Communication Control Block
The communication control block is designed to detect circuit signals (e.g., CNG,
DTMF). It also uses the main CPU on the image processor PCB to control the 33.6kbps
modem, thus modulating or demodulating transmission/reception data.
Memory Function
The 16MB (as mounted) SDRAM used for storage of image data is capable of holding
image data equivalent to about 100 pages (about 2 MB) of Canon FAX Standard Chart
No. 1. The image data will also be backed up for about 1 hr by the vanadium lithium sec-
ondary battery in the event of a power shortage. The 128KB SRAM, on the other hand, is
designed to store registered data (e.g., user data, service data), and the data will be backed
up by means of a lithium battery when the machine is turned off (for about 5 yr).
Image Storage DIMM Slot (option)
The RAM-DIMM (32MB x 2) fitted to the slot is used for storage of image data for
transmission and reception.
b. NCU PCB
2-line/4-line Conversion Circuit
The signal from a 2-line type telephone line is converted into transmission signals and
reception signals (4 lines). It also prevents transmission signals from the modem from
coming into the reception circuit.
Dial Pulse Generating Circuit
The dial pulse generating circuit is designed to generate dial pulses by turning on and
off the relay inside the circuit in response to the control signal from the image processor
PCB, thus sending the dial signals from the fax using the telephone line.
Off-Hook Detection Circuit
When the telephone line connected to the telephone terminal or the handset (option) is
in off-hook state, the direct current flowing to the circuit is detected to find out that the
system is in off-hook state.
Line Voltage Conversion Circuit
The primary side of the NCU PCB is controlled by a +48V DC circuit voltage; its direct
component is cut using a capacitor so that only the voice signal is connected into a mo-
dem-level voltage.
c. Modular PCB
Telephone Line Interface
The signals from the 3 modular jacks (for telephone line, for telephone connection, for
option handset) is forwarded to the line voltage conversion circuit of the NCU PCB for
communication of signals from a fax to the telephone line.