Users Guide

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 built-in ports, without having to reconfigure the card.
When the system 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 you add an internal modem card with a port configured as COM1, the system then sees logical COM1 as