Dell PowerEdge 2500SC User Manual

Page 5

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Port designations are used, for example, in software installation procedures that include a step in which you identify the port to which a printer is attached, thus telling
the software where to send its output. (An incorrect designation prevents the printer from printing or causes scrambled print.)

Adding an Expansion Card Containing Serial or Parallel Ports

The 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 system 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 system 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

If you reconfigure your hardware, you may need pin number and signal information for the serial port connectors.

Figure B-2

illustrates the pin numbers for the serial

port connectors and

Table B-1

defines the pin assignments and interface signals for the serial port connector.

Figure B-2. Pin Numbers for the Serial Port Connectors

Table B-1. Pin Numbers for the Serial Port
Connectors

Pin

Signal I/O Definition

DCD I