IBM eServer 240 xSeries User Reference Manual page 102

Serial ports
Your server comes with two serial ports. (See "Input/output connectors and
expansion slots" on page 11 for the locations of the connectors.) These ports are
used to communicate with printers, plotters, external modems, scanners, and
auxiliary terminals. These ports also enable you to transfer data between
computers.
Serial ports can transfer data asynchronously, which means that they can transmit
any number of characters at any time, with no restriction on the duration of the
pauses between characters.
The serial ports can transmit and receive data and commands at rates of from 300
bits per second up to 115 000 bits per second.
Serial port A is shared by the operating system and the integrated Advanced
System Management Processor. Serial port B can be used only by the operating
system.
Each serial port has a 9-pin, male D-shell connector on the back of the server. The
pin-number assignments of this connector conform to the industry standard.
The following table shows the pin-number assignments for the serial-port
connectors.
When you turn on your server, the POST routine assigns the serial ports to specific
communication port addresses.
Some application programs use only certain ports, and some modems are designed
for use only at certain communication port addresses. You might need to use the
Configuration/Setup Utility program to change communication port address
assignments to resolve conflicts.
Management port C
Your server has a dedicated system-management I/O port. This port can be used
to attach a modem that is dedicated to communication with the Advanced System
Management Processor.
The connector on the back of the server and the pin-number assignments are the
same as for the serial ports.
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IBM xSeries User's Reference
Table 4. Serial port pin-number assignments
Pin Signal
1 Data carrier detect
2 Receive data
3 Transmit data
4 Data terminal ready
5 Signal ground
5
1
6 9
Pin Signal
6 Data set ready
7 Request to send
8 Clear to send
9 Ring indicator