Interface Selection - Epson DFX-9000 Service Manual

Epson DFX-9000

1.2.8.7 Interface selection

The printer has 4 interfaces: the parallel interface, the USB interface, the
Serial interface, and the Type-B optional interface. These interfaces are
selected manually by SelecType, or selected automatically.
Manual selection
Any one of 4 interfaces can be selected by SelecType.
Automatic selection
The automatic interface selection is enabled by SelecType. In automatic
interface selection mode, the printer is initialized to the idle state. It
scans all interfaces once it is powered on. The interface that receives
data first is selected. When the host stops data transfer and the printer is
in stand-by state for the seconds specified by SelecType, the printer is
returned to the idle state. As long as the host sends data or the printer
interface is in a busy state, the printer keeps the interface selection status
as it is.
Interface state and interface selection
When the parallel interface is not selected, the interface gets into a busy
state. When the USB interface is not selected, the interface responds to
an OUT transaction with NAK handshake. When the serial interface is
not selected, the interface sends XOFF and sets the DTR signal to
MARK. When the Type-B serial interface card is installed and it is not
selected, the interface sends XOFF and sets the DTR signal to MARK.
When the optional interface is not selected, the printer sets the
"OFFLINE" bit of the MNSTS register to the optional interface. When
the printer is initialized or returned to the idle state, the parallel interface
enters a ready state, the USB interface is ready to respond to an OUT
transaction with an ACK handshake, the serial interface sends XON and
sets the DTR to SPACE, and the printer resets the "OFFLINE" bit of the
MNSTS register to the optional interface.
Product Description
Note that interrupt signals, such as the -INIT signal on the parallel
interface, and the software reset on the USB interface, are not effective
while that interface is not selected.
1.2.8.8 Host data transfer timeout prevention
Generally, host computers abandon data transfer to peripherals when a
peripheral is in a busy state for an extended period of time. To prevent
this kind of timeout, the printer continues to receive data very slowly,
several bytes per minute, even if the printer is in a busy state. This
slowdown starts when there are only a few thousands of bytes of
remaining space in the input buffer. When the input buffer is completely
full, the printer enters a busy state and stops receiving data.
This host-timeout prevention scheme operates on the parallel I/F and
on the USB I/F.
This function is not required when IEEE 1284.4 mode is enabled on
the parallel or USB interface.
Basic specifications
Revision B
37