Dell PowerEdge 4400 User Manual
Page 38
The computer system has an autoconfiguration capability for the serial ports. This feature lets you add an expansion card containing a serial port
that has the same designation as one of the integrated ports, without having to reconfigure the card. When the computer detects the duplicate
serial port on the expansion card, it remaps (reassigns) the integrated port to the next available port designation.
Both the new and the remapped COM ports share the same interrupt request (IRQ) setting, as follows:
COM1, COM3: IRQ4 (shared setting)
COM2, COM4: IRQ3 (shared setting)
These COM ports have the following I/O address settings:
COM1: 3F8h
COM2: 2F8h
COM3: 3E8h
COM4: 2E8h
For example, if you add an internal modem card with a port configured as COM1, the computer then sees logical COM1 as the address on the
modem card. It automatically remaps the integrated serial port that was designated as COM1 to COM3, which shares the COM1 IRQ setting.
(Note that when you have two COM ports sharing an IRQ setting, you can use either port as necessary but you may not be able to use them both at
the same time.) If you install one or more expansion cards with serial ports designated as COM1 and COM3, the corresponding integrated serial
port is disabled.
Before adding a card that remaps the COM ports, check the documentation that accompanied your software to make sure that the software can be
mapped to the new COM port designation.
To avoid autoconfiguration, you may be able to reset jumpers on the expansion card so that the card's port designation changes to the next
available COM number, leaving the designation for the integrated port as is. Alternatively, you can disable the integrated ports through the System
Setup program. The documentation for your expansion card should provide the card's default I/O address and allowable IRQ settings. It should also
provide instructions for readdressing the port and changing the IRQ setting, if necessary.
If you add an expansion card containing, for example a parallel port configured as LPT1 (IRQ7, I/O address 378h), you must go into the
system
setup
program to remap the integrated parallel port.
For general information on how your operating system handles serial and parallel ports, and for more detailed command procedures, see your
operating system documentation.
Serial Port Connectors
numbers for the serial port connectors and defines the pin assignments and interface signals for the serial port connector.
Figure 2. Pin Numbers for the Serial Port Connectors
Parallel Port Connector
numbers for the parallel port connector and defines the pin assignments and interface signals for the parallel port connector.
Figure 3. Pin Numbers for the Parallel Port Connector
Pin
Signal
I/O
Definition
1
DCD
I
Data carrier detect
2
SIN
I
Serial input
3
SOUT
O
Serial output
4
DTR
O
Data terminal ready
5
GND
N/A
Signal ground
6
DSR
I
Data set ready
7
RTS
O
Request to send
8
CTS
I
Clear to send
9
RI
I
Ring indicator
Shell
N/A
N/A
Chassis ground
Pin
Signal
I/O
Definition
1
STB#
I/O
Strobe
2
PD0
I/O
Printer data bit 0
3
PD1
I/O
Printer data bit 1
4
PD2
I/O
Printer data bit 2
5
PD3
I/O
Printer data bit 3
6
PD4
I/O
Printer data bit 4
7
PD5
I/O
Printer data bit 5
8
PD6
I/O
Printer data bit 6