Epson DFX-9000 Service Manual page 45

Epson DFX-9000
1.2.8.9 IEEE 1284.4 protocol
The packet protocol described by IEEE 1284.4 is supported on the
parallel I/F and the USB I/F. Two modes of the IEEE 1284.4 protocol,
"Off" and "Auto", are available, and are selected through SelecType.
Refer to 1.3.3 SelecType functions setting
The packet protocol options "Off" and "Auto" in SelecType mode are
effective for both parallel and USB I/F.
Auto: Communication is carried out in the conventional mode until
a magic string (1284.4 synchronous commands) is received.
Once a magic string is received, communication in IEEE
1284.4 packet mode starts.
Off: Communication is carried out in the conventional mode.
When printing from a Windows-based printer driver, set the packet
protocol to "Auto".
The functionality of the "Off" mode in IEEE 1284.4 protocol is not
guaranteed on the USB I/F.
NOTE: The packet protocol of IEEE 1284.4 allows a device to carry
on multiple exchanges or conversations that contain data
and/or control information with another device at the same
time across a single point-to-point link. However, the
protocol is not a device control language. It does provide
basic transport-level flow control and multiplexing services.
The multiplexed logical channels are independent of each
other and the blocking of one has no effect on the others.
The protocol operates over IEEE 1284.
Product Description
(p.46).
Basic specifications
Revision B
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