Epson EPL-9000 Service Manual page 29

General Description
indicates an
Note 1: ( )
Note 2: 'US", and
Note3: Although the
for mode if selected through
Note4: SD+, SD-:
Serial ASCII data output from the printer.
HIGH level; when SD+ voltage is higher than SD-voltage.
LOW level; when SD+ voltage is less than SD-voltage.
Logic O is "SPACE" and logic 1 is "MARK" state must be maintained between
transmitted character codes.
Serial ASCII data input from the computer.
HIGH level; when
LOW level; when
Logic O is "SPACE" and logic 1 is "MARK" state must be maintained between
transmitted character codes.
Handshaking
When the vacant area for data
cede or sets the
Once the vacant area for data
or sets the to
Protocol
There are two types of protocols, as listed below, and each of them can be designated by
independently.
protocol
is used to execute the
the printer is ready to receive data, and to LOW when conditions indicate an error or that the
receiving buffer is full.
When the error is cleared and the printer returns to on-line mode, the signal returns to HIGH.
When is used to set the
only when is at the HIGH level (DSR is always considered HIGH when the
setting for is OFF).
X-ON/X-OFF
is used to execute the X-ON/X-OFF protocol. The X-OFF
indicates an error, and the printer warns the host to stop data transmission within 128 characters.
No further X-OFF codes are sent in response to additional data received from the host after the
X-OFF code has been sent once. The
error are cleared.
When the remaining capacity of the receive buffer reaches 256 characters, X-OFF
once. It is sent only once, even if there are multiple errors. The printer goes on line automatically at
power on, and outputs an X-ON code. Transmission of
1-18
signal, which is
states can be selected through
and
voltage is higher than
voltage is less than
the input buffer drops to 256 bytes, the printer outputs an
to LOW, indicating that the printer cannot receive more data.
buffer recovers to
indicating that the printer is again ready to receive data.
control protocol. The
OFF,
transmission is independent of the
(DCl) code is output after
voltage.
voltage.
bytes, the printer outputs an X-ON code
signal is set to HIGH when
is always set HIGH. The printer transmits
state.
code is output if status
renditions given in the
codes can be defined by
' Manual
used
.
is output
Rev.