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5. TROUBLE SHOOTING
5-1. Explanation of the function for each PCB
1.M-1(Main) PCB
This PCB contains CPU and all of the control circuits, the following
functions are included.
1)LSI so called FAX ENGINE (TC35168F)
(1) 8-Bit CPU
(2) Modem :
- Modulation and Demodulation of signals
- Tone signal generation and detection
- Touch Tone Signal (DTMF) generation
- Pre-recorded Voice Prompt generation
- Melody generation (when conversation is put on hold)
(3) Codec:
- Coding and Decoding of image signal
(4) Image Signal Processor :
- Driving of CIS (Contact Image Sensor)
- Convert analog signal to digital signal (two or multi value)
- Reduction of image
(5) DMA (Direct Memory Access) Controller :
- Used when transferring the data from image signal processor to line
memory, from line memory to modem, to thermal head and codec.
) Real Time Clock
) Stepping Motor Control
) Thermal head Control
) V/O ports control :
- NCU
- TEL
- Mechanism
- Operation Panel
- LCD control
2)1-Mbits EPROM :
This PROM contains the program to control CPU.
3)64-Kbits SRAM (2-pcs) :
Used as line memory for memorizing image data temporarily or various
data memory.
4)Memory back-up control :
Used to keep the stored data of SRAM and Clock.
5)NCU interface circuit :
This is a interface circuit for connecting the NCU and Modem.
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