National Instruments PCI-232/2, Getting Started, Page: 54 / 64

Appendix E Troubleshooting and Common Questions
PCI Serial for Windows 95 E-4 © National Instruments Corporation
How can I determine which port is associated with COMx?
Refer to the section Determine Which Physical Port Is Associated with
COMx , in Chapter 2, Installation and Verification .
How can I name National Instruments serial ports COM1, COM2,
COM3, or COM4?
Table E-1 lists standard DOS-base addresses for serial ports.
In most cases, Windows 95 does not assign names COM1 through COM4
to the serial hardware. Rather, it names the ports starting with COM5. If
you assign any of the base addresses in Table D-1 to a National Instruments
serial port, Windows 95 automatically changes the COM port name to the
corresponding one listed in this table. You do not need to change the IRQ
setting for this name change to occur. To change the base address, refer to
the
Selecting Conflict-Free Resources section earlier in this appendix.
How do I change the resources assigned to the serial interface?
Because the serial interfaces are single physical devices that support
multiple ports, they are registered as “multi-function adapters” in the
Device Manager. Each port is a child device listed under Ports (COM &
LPT). Windows 95 does not allow the resources of the multi-function child
devices to be changed directly.
To change the resources of ports on serial boards from within the Device
Manager, you must open the Multi-function adapters class and
double-click on the Multi-function Parent item that corresponds to your
National Instruments serial interface. Use the Resources page to change
the resources. Any resource changes are automatically reflected to the child
devices. Figure E-1 shows the Multi-function adapters class in the Device
Manager.
Table E-1. Standard DOS-Based Addresses
COM Port Base Address
COM1 3f8
COM2 2f8
COM3 3e8
COM4 2e8