Ricoh B230 Service Manual
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Service RAM Addresses SM 121 B786 B786 Fax Option Defaults Area 6BEC03 6BEC04 NA F4 01 EU F4 01 ASIA F4 01 6BEC05(H) – Dial tone detect judge time (20 ms) Defaults: NA: 64, EU: 1B, ASIA: 32 6BEC06(H) – Dial tone disconnect permission time (20 ms) Defaults: NA: 11, EU: 0F, ASIA: 11
Overview B786 122 SM 5. DETAILED SECTION DESCRIPTIONS 5.1 OVERVIEW The basic fax unit consists of two PCBs: an FCU and an MBU. The FCU controls all the fax communications and fax features, in cooperation with the controller board. The MBU contains the ROM and SRAM. Also, the FCU has an NCU circuit. Fax Options: 1. Extra G3 Interface option: This provides one more analog line interface. This allows full dual access. Two extra G3 interface options can be installed. 2. Memory Expansion: This expands the SAF memory and the page memory (used for image rotation); without this expansion, the page memory is not big enough for image rotation at 400 dpi, so transmission at 400 dpi is not possible.
Boards SM 123 B786 B786 Fax Option 5.2 BOARDS 5.2.1 FCU The FCU (Facsimile Control Unit) controls fax communications, the video interface to the base copier’s engine, and all the fax options.. FACE3 (Fax Application Control Engine) ƒ CPU ƒ Data compression and reconstruction (DCR) ƒ DMA control ƒ Clock generation ƒ DRAM backup control Modem (FAME) ƒ V.34, V33, V17, V.29, V.27ter, V.21, and V.8 DRAM ƒ The 16 MB of DRAM is shared as follows. SAF memory : 4MB Working memory : 8MB Page memory : 4MB ƒ The SAF memory is backed up by a rechargeable battery. Memory Back-up ƒ A Rechargeable battery backs up the SAF memory (DRAM) for 1 hour.
Boards B786 124 SM 5.2.2 MBU On this board, the flash ROM contains the FCU firmware, and the SRAM contains the system data and user parameters. Even if the FCU is changed, the system data and user parameters are kept on the MBU board. ROM ƒ 3MB flash ROMs for system software storage 2MB (16bit x 1MB) + 1MB (16bit x 512K) SRAM ƒ The 256KB SRAM for system and user parameter storage is backed up by a lithium battery. Memory Back-up ƒ A lithium battery backs up the system parameters and programmed items in the SRAM, in case the base copiers main switch is turned off. Switches Item Description SW1 Switches the SRAM backup battery on/off.
Boards SM 125 B786 B786 Fax Option 5.2.3 SG3 BOARD The SG3 board allows up to three simultaneous communications when used in combination with the FCU and optional G3 boards. The NCU is on the same board as the common SG-3 board. This makes the total board structure smaller. But, the specifications of the SG3 board do not change. NCCP (New Communication Control Processor) ƒ Controls the SG3 board. ƒ CPU (RU30) ƒ DPRAM (Dual Port RAM): Handshaking with the FCU is done through this block. ƒ DMA controller ƒ JBIG ƒ DSP V34 modem (RL5T892): Includes the DTMF Receiver function ƒ DCR for MH, MR, MMR, and JBIG compression and decompression FROM ƒ 1Mbyte flash ROM for SG3 software storage and modem software storage SDRAM ƒ 4Mbyte DRAM shared between ECM buffer, line buffer, and working memory
Boards B786 126 SM AFE (Analog Front End) ƒ Analog processing CODEC (COder-DECoder) ƒ A/D & D/A conversions for modem REG ƒ Generates +3.3 V from the +5V from the FCU
Video Data Path SM 127 B786 B786 Fax Option 5.3 VIDEO DATA PATH 5.3.1 TRANSMISSION Memory Transmission and Parallel Memory Transmission The base copiers scanner scans the original at the selected resolution in inch format. The BICU processes the data and transfers it to the FCU. ƒ When scanning a fax original, the BICU uses the MTF, independent dot erase and thresholding parameter settings programmed in the fax unit’s scanner bit switches, not the copiers SP modes. Then, the FCU converts the data to mm format, and compresses the data in MMR or raw format to store it in the SAF memory. If image rotation will be done, the image is rotated in page memory before compression. At the time of transmission, the FCU decompresses the stored data, then re-compresses
Video Data Path B786 128 SM and/or reduces the data if necessary for transmission. The NCU transmits the data to the line. Immediate Transmission The base copiers scanner scans the original at the resolution agreed with the receiving terminal. The BICU video processes the data and transfers it to the FCU. ƒ When scanning a fax original, the BICU uses the MTF, independent dot erase and thresholding parameter settings programmed in the fax unit’s scanner bit switches, not the copiers SP modes. Then the FCU stores the data in page memory, and compresses the data for transmission. The NCU transmits the data to the line. JBIG Transmission ƒ Memory transmission: If the receiver has JBIG compression, the data goes from the DCR to the QM-Coder. Then the NCU transmits the data to the line. When an optional G3 unit (SG3) is installed and PSTN2 is selected as the line type, JBIG compression is available, but only for the PSTN-2 line. ƒ Immediate transmission: If the receiver has JBIG compression, the data goes from the page memory to the QM-Coder. Then the NCU transmits the data to the line. When an optional G3 unit (SG3) is installed and PSTN2 is selected as the line type, JBIG compression is available, but only for the PSTN-2 line. Adjustments Priority for the line used for G3 transmissions (PSTN 1/PSTN 2 or 3): System switch 16 bit 1
Video Data Path SM 129 B786 B786 Fax Option 5.3.2 RECEPTION First, the FCU stores the incoming data from either an analog line to the SAF memory. (The data goes to the FACE3 at the same time, and is checked for error lines/frames.) The FCU then decompresses the data and transfers it to page memory. If image rotation will be done, the image is rotated in the page memory. The data is transferred to the BICU. If the optional G3 unit is installed, the line that the message comes in on depends on the telephone number dialled by the other party (the optional G3 unit has a different telephone number from the main fax board). JBIG Reception When data compressed with JBIG comes in on PSTN-1 (the standard analog line), the data is sent to the QM-CODER for decompression. Then the data is stored in the page memory, and transferred to the BICU. When data compressed with JBIG comes in on PSTN-2 (optional extra analog line), the data is sent to the QM-CODER on the SG3 board for decompression.
Fax Communication Features B786 130 SM 5.4 FAX COMMUNICATION FEATURES 5.4.1 MULTI-PORT When the optional extra G3 Interface Unit is installed, communication can take place at the same time through the two or three lines at once. Option Available Line Type Available protocol Combinations Standard only PSTN G3 Extra G3 Interface Unit (single) PSTN + PSTN G3 + G3 Extra G3 Interface Unit (double) PSTN + PSTN +PSTN G3 + G3 +G3 5.4.2 DOCUMENT SERVER The base copiers scanner scans the original at the selected resolution. The IPU video processes the data and transfers it to the controller board. Then the controller stores the data in the page memory for the copier function, and compresses the data in MMR (by software) to store it in the HDD. If image rotation will be done, the image is rotated in the page memory before compression. For transmission, the stored image data is transferred to the FCU. The FCU