Canon FAX L1000 Service Manual page 587

•The Flow of Print Data
The main unit's printing operations are done totally independently when faxing and
printing, but data communications between the PDL board and the ECNT board are all
done through the SCNT board.
When printing, when PDL data is sent from the PC go the PDL board (when using the
optional ethernet board), the PDL board converts the PDL data into print data and sends this
converted data to the TWINS board.
When the PDL board and the TWINS board transmit print data, the flow of data is divided
in to two categories, control (nCMD, nRDY, etc) and image (nVDO, nBD, nTOP),
depending on the signal type.
a.Control Signal
(1) The control signal is sent from the PDL board to the TWINS IC, passes through the
data bus, and is forwarded to the system controller IC on the SCNT board.
(2) The control signal sent to the system controller IC is sent to the ECNT board as-is.
(3) The ECNT board sends a signal to the SCNT board system controller IC in response to
the control signal it received.
(4) The response signal is forwarded from the system controller IC to the TWINS IC,
passing through the data bus, and is sent to the PDL board.
PDL data from PC
Ethernet Board
PDL data from Network
Figure 5-90 Flow of Print Data 1
TWINS Board
1
nRDY etc.
Video
TWINS
interface
4
PDL Board
3
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FAX-L1000 Chapter 5: Appendix
1
System
Data
controller
bus
IC
4
2
ECNT Board
IC
SCNT Board