Adding An Expansion Card Containing Serial Or Parallel Ports - Dell 4100 User Manual

Adding an Expansion Card Containing
Serial or Parallel Ports
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 built-in ports, without having to reconfigure
the card. When the computer detects the duplicate serial
port on the expansion card, it remaps (reassigns) the built-
in 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 a technician adds 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 built-in serial port that was des-
ignated 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 neces-
sary 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 corre-
sponding built-in serial port is disabled, as described in
"Serial Port 1" and "Serial Port 2" in Chapter 4.
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, the technician may be able to
Figure B-1. I/O Ports and Connectors
reset jumpers on the expansion card so that its port desig-
nation changes to the next available COM number,
leaving the designation for the built-in port as is. Alterna-
tively, they can disable the built-in ports through the
System Setup program. The documentation for your
expansion card should provide the card's default I/O
B-2 Dell PowerEdge 4100/180 and 4100/200 Systems User's Guide