3JF-1
2-2-1
2-2-1 Fax control PCB
ASIC
U061
SDRAMs
4M
◊
16 bit
◊
2
(upper/lower)
Optional
memory
Maximum
64 MB
SSCG
LVC
LVC
LVC
Oscillator
(44 MHz)
RTL
Oscillator
Backup
circuit
RTC
power
supply
Flash memories
1M
◊
16 bit
◊
2
(upper/lower)
Modem LSI
U074
Analog
circuit
Backup
circuit
NCU
PCB
Connect to
the main PCB
Connect to
the main PCB
Engine
IF
(1/2)
Engine
IF
(2/2)
Lithium
battery
FAX control PCB
Lithium battery
backup circuit
LVC
CPU
U011
(133 MHz)
1.9 V
regulator
3.3 V
regulator
3.3 V
3.3 V
3.3 V
1.9 V
Data bus
Address bus
5 V
5 V
5 V
5 V
5 V
5 V
1.9 V
SGND, PGND
24 V
5 V
12 V
12 V
12 V
5 V
12 V
24 V
12 V
regulator
3.3 V
3.3 V
44 MHz
44 MHz
44 MHz
32 bit
32 bit
32 bit
/FAXSLEEP/WAKEUP
8 bit
3.3 V
2.4 V
Speaker
circuit
Speaker
LVC
U021
U051
U052
U022
Backup
battery
(NiMH)
1.9 V
Figure 2-2-1
Fax control PCB block diagram
The fax control PCB (FCPCB) controls the overall fax operation.
To transmit a fax, image data scanned by the optical section of the copier is processed by the main PCB (MPCB) and then
sent to the fax control PCB (FCPCB). Received image data is first stored in the bitmap area of the SDRAM U021/U022 page
by page and compressed using the MH, MR, MMR or JBIG method. The data is then stored in the image memory area of
the SDRAM U021/U022 and sent to the modem LSI U074 to be modulated from digital signal to analog signal before it is
sent to the telephone line via the NCU PCB (NCUPCB). To receive a fax, analog image data received from the telephone
line via the NCU PCB (NCUPCB) is sent to the modem LSI U074 and, after demodulation into digital signals, stored in the
image memory area of the SDRAM U021/U022. The image data is then decompressed and converted into the bitmap area
of the SDRAM U021/U022 page by page and sent to the ASIC U061 for resolution conversion and smoothing, and is passed
to the main PCB (MPCB) as print image data.
