Using The Rs-232C Serial Interface - Lexmark X940E Technical Reference

Serial Interface
The serial interface allows data to flow back and forth between the computer and the
printer. However, the serial interface transfers data at a slower rate than the parallel
interface.
If a serial connector is required, you may be able to install an RS-232C Serial Interface
Card, an External Serial Adapter, or an RS-232C Serial/Parallel 1284-C Interface
Card. See your printer documentation for more information.
When using the serial interface, your printer has the following differences from the
serial interface on some other printers:

Using the RS-232C Serial Interface

RS-232C Serial Cable Pin Assignments
The RS-232C serial cable appears as follows:
Table 8-3: Dedicated Serial Connector Pin Assignments (RS-232C)
Pin
1
2
3
•
The printer returns XON/XOFF with 2 stop bits in all cases.
•
The printer does not support DTR inversion.
25-Pin
D-Shell
13 25
(Male)
1 14
Printer
Side
Signal Direction
GND
TXD Out
RXD In
8-11
25-Pin
D-Shell
(Female)
Computer
Side
Description
Frame Ground
Transmit Data. The pin transmits data to your computer or
terminal.
Receive Data. The pin receives data from your computer or
terminal.
Interfaces
13 25
1 14