Basic Configurations for COM Ports in Windows 95

• Microsoft Windows 95

SUMMARY

Windows 95 includes a set of "Basic Configurations" for communications (COM) ports. These configuration options make it easier for you to avoid hardware conflicts by letting you easily change the settings a COM port uses.

These Basic Configurations provide the following:

• A default configuration for each COM port. You cannot change this default setting.
• Additional configurations for each port that lets you edit the IRQ setting. These configurations do not let you change I/O addresses.
• Additional configurations for each port that lets you edit both the IRQ and the I/O range.

MORE INFORMATION

Basic Configurations are determined by the following table:

   Basic
   Configuration   IRQ Setting   Editable?   I/O Setting   Editable?
   -----------------------------------------------------------------
   0                    4           No        03F8-03FF        No
   1                    4           Yes       03F8-03FF        No
   2                    3           No        02F8-02FF        No
   3                    3           Yes       02F8-02FF        No
   4                    4           No        03E8-03EF        No
   5                    4           Yes       03E8-03EF        No
   6                    3           No        02E8-02EF        No
   7                    3           Yes       02E8-02EF        No
   8                Variable        Yes       Variable         Yes

COM 2 defaults to Basic Configuration 2. The IRQ can be changed by selecting Basic Configuration 3.

COM 3 defaults to Basic Configuration 4. The IRQ can be changed by selecting Basic Configuration 5.

COM 4 defaults to Basic Configuration 6. The IRQ can be changed by selecting Basic Configuration 7.

Basic Configuration 8 can be used to configure additional COM ports because it lets you change the IRQ and the I/O address.

Example

The following is a sample procedure for changing the IRQ for COM 1:

1. Click the Start button on the taskbar.

2. On the Settings menu, click Control Panel, then double-click the System icon.

   NOTE: You can skip steps 1 and 2 if you use the right (secondary) mouse button to click the My Computer icon and then click Properties.

3. Click the Device Manager tab, double-click Ports (COM & LPT), then double-click Communications Port (COM1).

4. Click the Resources tab.

   NOTE: COM 1 defaults to Basic Configuration 0, and the settings are according to the table above.

5. Click the arrow next to the Setting Based On box, and click Basic Configuration 1.

6. Under Resource Settings, double-click Interrupt Request (or IRQ), then click the up or down arrow to change the Value field setting.

7. Click OK and restart Windows when you are prompted.