Panasonic KX-FT981LA-B, Service Manual

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KX-FT981LA-B / KX-FT987LA-B
6.4. Facsimile Section
6.4.1. Image Data Flow During Facsimile Operation
Copy (Fine, Super-Fine, Photo)
1. Line information is read by CIS (to be used as the reference white level) via route (1), and is input to IC1. Refer to Block Dia-
gram (P.21)
2. In IC1, the data is adjusted to a suitable level for A/D conversion in the Analog Signal Processing Section, and via route (2) it
is input to A/D conversion (8 bit). After finishing A/D conversion, the data is input to the Image Processing Section via route
(3). Then via route (4) and route (5), it is stored in RAM as shading data.
3. The draft’s information that is read by CIS is input to IC1 via route (1). After it is adjusted to a suitable level for A/D conversion
via route (2), the draft’s information is converted to A/D (8 bit), and it is input to the Image Processing Section. The other side,
the shading data which flows from RAM via route (6) and route (7), is input to the Image Processing Section. After finishing
the draft’s information image processing, white is regarded as "0" and black is regarded as "1". Then via routes (4) and (5),
they are stored in RAM.
4. The white/black data stored as above via routes (6) and (8) is input to the P/S converter. The white/black data converted to
serial data in the P/S converter is input to the Thermal Head via route (9) and is printed out on recording paper.
Note:
Fine: Reads 3.85 lines/mm
Super Fine: Reads 7.7 lines/mm
Photo: Reads 15.4 lines/mm
Transmission
1. Same processing as Copy items 1 - 3.
2. The data stored in the RAM of IC1 is output from IC1 via routes (6) and (10), and is stored in the system bus.
Via route (11), it is stored in the communication buffer inside DRAM (IC4).
3. While retrieving data stored in the communication buffer synchronous with the modem, the CPU (inside IC1) inputs the data to
the modem along route (12), where it is converted to serial analogue data and forwarded over the telephone lines via the
NCU Section.
Reception
1. The serial analog image data is received over the telephone lines and input to the modem via the NCU section, where it is
demodulated to parallel digital data. Then the CPU (IC1) stores the data in the communication buffer DRAM (IC4) along route
(11).
2. The data stored in DRAM (IC4) is decoded by the CPU (IC1) via route (12), and is stored in RAM via routes (13) and (5).
3. Same processing as
Copy item 4.