Serial Interface - Epson LX-300 Service Manual

LX-300+
Table 1-15. Connector Pin Assignment and Signals
Return
Pin
Signal Name GND
No.
Pin
35 +5V --
17 Chassis --
16, 33,
GND --
19-30
15, 34 NC --
* 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): -3V to -25V
SPACE (logical 0): +3V to +25V
Word length: Start bit:
Data bit:
Parity bit: Odd, Even, Non, Ignore
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.
Product Description
In/Out Functional Description
This line is pulled up tp +5V
Out
through 1.0 kΩ resister.
-- Chassis GND.
Signal GND.
--
-- Not connected.
1 bit
8 bit
1 bit or more
Interface Specifications
Connector: 25 pin subminiature D-shell connector (female)
Table 1-16. Connector Pin Assignment and Signals
Pin
Signal Name In/Out Functional Description
No.
2 TXD Out Transmit data.
Indicates that the printer is ready to receive data
20 DTR Out
or not.
11 REV Out Connected directly to the DTR signal.
Request to send. Always SPACE level when the
4 RTS Out printer is powered on. Pulled up to +12V via
4.7KΩ resistor.
3 RXD In Receive data.
7 Signal GND -- Signal GND
1 Chassis GND -- Chassis GND
other NC -- Not used. Not connected.
* In/Out shows the direction of signal flow from the printer's point of view.
Revision A
22