Epson Stylus Pro 5000 Service Manual page 20

EPSON Stylus Pro 5000
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Automatic Selection:
The automatic interface selection is enabled by the default setting
mode. In this automatic interface selection mode, the printer is
initialized to the idle state scanning which interface receives data
when it is powered on. Then the interface that receives data first is
selected. When the host stops data transfer and the printer is in the
stand-by state for the seconds, the printer is returned to the idle
state. As long as the host sends data or the printer interface is busy
state, the selected interface is let as it is.
Following explains conditions of other interfaces when a particular interface
is selected.
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When the parallel interface is not selected, the interface gets into
BUSY state. At this time, LH signal is set to "L". That means blocking
power supply and no responds from 1284. Therefore, it is necessary
for the host, which requires Reverse transfer, to check LH state.
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When the serial interface is not selected, the interface sets the DTR
signal MARK.
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When the optional interface is not selected, Off-Line bit is set to Main
Status Register(MNSTS).
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When the printer is initialized or returned to the idle state, Parallel
interface becomes the ready condition and DTR of serial interface
becomes SPACE(Low) condition and reset off-line bit of Main Status
Register(MNSTS)to, option interface.
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/INIT signal on the parallel interface is not effective while that
interface is not selected or nibble Mode, ECP Mode.
Rev.A
Chapter1 Product Description
1-10