Ricoh Aficio 220 Service Manual page 544

Memory Transmission and Parallel Memory Transmission
The base copier's scanner scans the original at the selected resolution in inch
format. The BiCU processes the data and transfers it to the FCU.
NOTE: When scanning a fax original, the BiCU uses the MTF and thresholding
parameter settings programmed in the fax unit's scanner bit switches, not
the copier's 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 (see
section 2-2-2), the image is rotated in page memory before compression.
At the time of transmission, the FCU decompresses the stored data, then re-
compresses and/or reduces the data if necessary for transmission. Either the NCU
or CiG4 (optional) transmits the data to the line.
Immediate Transmission
The base copier's scanner scans the original at the resolution agreed with the
receiving terminal. The BiCU video processes the data and transfers it to the FCU.
NOTE: When scanning a fax original, the BiCU uses the MTF and thresholding
parameter settings programmed in the fax unit's scanner bit switches, not
the copier's SP modes.
Then the FCU stores the data in page memory, and compresses the data for
transmission. Either the NCU or CiG4 (optional) transmits the data to the line.
Note that ISDN G3 tx is not possible on the PSTN-2 line.
JBIG Transmission
• Memory transmission: If the receiver has JBIG compression, the data goes
from the FACE (DCR) to the EXFUNC board for JBIG compression. Then either
the NCU or CiG4 (ISDN G3) 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.
• Immediate transmission: If the receiver has JBIG compression, the data goes
from the page memory to the EXFUNC board for JBIG compression. Then either
the NCU or CiG4 (ISDN G3) 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
• Line used for G3 transmissions (PSTN or ISDN): System switch 0A bit 6
• Line used for G3 transmissions (PSTN 1/PSTN 2): System switch 16 bit 1
• Use of the PSTN-2 line (rx only, or both tx and rx): Communication switch 16 bit
5
• G3 line type: User parameter switch 6, bits 2 and 3
If this is at G3 auto selection, the machine can use either PSTN-1 or PSTN-2
If this is at PSTN-1, the machine will only use the PSTN-1 line.
SM 1-9
VIDEO DATA PATH
A265/A267