B-2 Dell PowerEdge 6100/200 System User’s Guide
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.
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
reset jumpers on the expansion card so that its port
designation changes to the next available COM number,
leaving the designation for the built-in port as is. Alterna-
tively, the technician can disable the built-in ports
through the system setup program (see Chapter 4) or
the system configuration utility (see Chapter 5). 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.
The built-in parallel port has autoconfiguration capability
through the system setup program. That is, if you set the
parallel port to its automatic configuration and add an
expansion card containing a port configured as LPT1
(IRQ7, I/O address 378h), the system automatically
remaps the built-in parallel port to its secondary address
(IRQ5, I/O address 278h). If the secondary port address
is already being used, the built-in parallel port is turned
off.
For general information on how your operating system
handles serial and parallel ports as well as for more
detailed command procedures, see your operating system
documentation.
Serial Port Connectors
If you reconfigure your hardware, you may need pin
number and signal information for the serial port connec-
tors. Figure B-2 illustrates the pin numbers for the serial
port connectors, and Table B-1 lists and defines the pin
assignments and interface signals for the serial port
connectors.
Figure B-2. Pin Numbers for the Serial Port
Connectors
5 — 1
9 — 6
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