Laser
Manual
General
Table 1-14. Serial Interface Connector Pin Assignments (Continued)
Pin No
6
7
—
.
8
9-19
20
21-25
Signal Name
SIGNAL GND
DCD
NC
NC
Handshaking
IN
IN
OUT
Description
Signal inputted to the printer. The printer can transmit data
through
while
is HIGH. X-ON/X-OFF, however, can
be transmitted regardless of
state. It can always be
ignored by setting
(Factory setting).
Ground reference (O
for signals.
Always ignored.
Not
Signal outputted by the printer. When the
signal is
HIGH, it indicates that the
signal can be received by the
printer. The
settings do not
control,
the signal level is HIGH while the printer power is on.
When
setting is used for
goes LOW in
case any of the error conditions.
The date
from host computer must be stopped within
128 characters after
goes LOW.
Not
When the vacant area for data in the input buffer drops to 128 bytes, the printer outputs an X-OFF
code sets the
level to LOW, indicating that the printer cannot receive more data.
Once the vacant area for data in the buffer recovers to 256 bytes, the printer outputs an X-ON code
or sets the
flag to HIGH, indicating that printer is again ready to receive data.
Protocol
There are three types of protocols, as listed below, and each of them can be designated by
independently.
■
protocol
is used to execute the
control protocol.
signal is set HIGH when
the printer is ready to receive data, and to LOW when conditions indicate an error or that the
receiving buffer is
When the error is cleared and the printer returns to on line mode, the signal returns to HIGH. When
is used to set the
control OFF,
is always set HIGH. The printer transmits
only when
is at the HIGH level
is always considered HIGH when the
setting
for
is OFF). X-ON/X-OFF transmission is independent from
state.
■
X-ON/X-OFF
protocol
is used to execute X-ON/X-OFF protocol. The X-OFF
code is output if status
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 X-ON
code is output after all conditions given in error
are cleared.
When the remaining capacity of the receive buffer reaches 128 characters, X-OFF
is output
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 X-ON/X-OFF codes can be defined by
■
Protocol
the EPSON GL
mode
is selected,
protocol is also supported.
Rev.
1-17
