Lexmark Optra T Reference page 336

RS-232C Serial Cable Pin Assignments
The RS-232C serial cable appears as follows:
Table 8-4: Dedicated Serial Connector Pin Assignments (RS-232C)
Pin
1
2
3
4
5
6
7
20
25-Pin
D-Shell
13 25
(Male)
1 14
Printer
Side
Signal Direction Description
GND Frame Ground
TXD Out Transmit Data. The pin transmits data to your computer or
terminal.
RXD In Receive Data. The pin receives data from your computer or
terminal.
RTS Out Request to Send. The printer sets this signal high and the
signal remains high while the printer is on.
CTS In Clear to Send. This pin is optionally used for serial data flow
control protocol when in serial mode.
DSR In Data Set Ready. This pin is optionally used for data
validation, depending on the Honor DSR setting, or flow
control, depending on the Serial Protocol setting.
GND Logic Ground
DTR Out Data Terminal Ready. This pin is optionally used for serial
data flow control protocol when in serial mode.
8-33
Interfaces
25-Pin
D-Shell
13 25
(Female)
1 14
Computer
Side