Epson LQ-2550 Technical Manual page 156

3.2.1 8143 Interface Board
When the RS-232C and 20 mA neutral current IOOP are in use, the printer will also SUPPOrt the 8143 '-"'
new serial interface.
Specifications
Synchronization
Bit rate
Word length
Start bit
Data bit
Parity bit
Stop bit
Signal level (EIA level)
Current loop
Handshaking
NOTE: The parallel interface cable, if connected, should be disconnected before using the 8143 board
because parallel interface input is used to read jumper settings and DIP switch status.
Jumper Settings
Table 3-2 shows the 8143 interface jumper settings.
J1 ON: "_lTY
J2
J3 ON: "TTY RXD" is pulled up to + 12V through 470 ohm resistor.
J4 ON: "TTY RXD RET" is connected to signal ground.
I
J 5
JRS
Selects input signal level
JNOR
Selects polarity to disable
data entry
JREV
—
Selects TTY TXD function
J X
Table 3-2. 8143 Jumper Settings
TXD" is pulled up to + 12V through 470 ohm resistor.
are pulled up to + 12V through 4.7K ohm resistor.
ON
OFF
OFF
ON
OFF
Asynchronous
B P S
75 to 19,200
7 8
or bit*
Odd, Even or Non-parity'
1 bit or more
MARK = logical "1"' (–3 to –27 V)
SPACE = logical "O" (+3 to +27 V)
MARK = logical "1" (current ON)
SPACE = logical "O" (current OFF)
By REV (DTR) signal or X-ON/X-OFF code
(Signal polarity can be inverted by jumper setting.)
setting on the 8143 board.
Function
MARK (RS-232C)
SPACE (Current loop)
Outputs DTR flag
3-2
OFF
Current loop level
ON
SPACE (Rs-232C)
MARK (Current loop)
ON
OFF
o u t p u t s
- / -
X O N X
signal
ON
J
O F F