Serial Interface - Epson LQ-300 + Service Manual

EPSON LQ-300+
Return
Pin No. Signal Name GND
Pin
17 Chassis --
16, 33,
GND --
19-30
15, 34 NC --
NOTE: In/Out shows the direction of signal flow from the printer's point of view.

1.3.3 Serial Interface

Synchronization: Asynchronous
Signal level: EIA-232D
MARK (logical 1):
SPACE (logical 0):
Word length: Start bit:
Data bit:
Parity bit:
Stop bit:
Baud rate: 300, 600, 1200, 2400, 4800, 9600 or 19200 bps
Handshaking: DTR signal and XON/XOFF
DTR=MAEK, XOFF: indicates that the printer cannot receive data.
DTR=MARK, XON: indicates that the printer is ready to receive data.
NOTE: The DTR signal is MARK and XOFF code (DC3, 13H) is transmitted
when the rest of the input buffer becomes 256 bytes. The DTR signal is
SPACE and XON code (DC1, 11H) is transmitted when the rest of the
input buffer is regained 256 byte.
Error handling: Parity error is only detected. Overrun error and
framing error are ignored.
Connector: 25 pin subminiature D-shell connector (female)
Product Description
In/Out Functional Description
-- Chassis GND.
Signal GND.
--
-- Not connected.
-3V to -25V
+3V to +25V
1 bit
7 bit, 8 bit
Odd, Even, Non, Ignore
1 bit or more
Pin
Signal Name In/Out
No.
2 TXD
20 DTR
11 REV
4 RTS
3 RXD
7 Signal GND
1 Chassis GND
other NC
NOTE: In/Out shows the direction of signal flow from the printer's point of view.
INTERFACE
Functional Description
Out Transmit data.
Out Indicates that the printer is ready to receive data or not.
Out Connected directly to the DTR signal.
Request to send. Always SPACE level when the printer is
Out
powered on. Pulled up to +12V via 4.7KΩ resistor.
In Receive data.
-- Signal GND
-- Chassis GND
-- Not used. Not connected.
Revision C
15