Microsoft KB Archive/78967

= FastTips: Using a Modem with Windows 3.0 Questions & Answers =

ID: Q78967

SUMMARY
This article contains the complete text of the &quot;Using a Modem with Windows 3.0&quot; fax script.

This fax script is available to customers who call the Microsoft FastTips Service for Operating Systems at (800) 936-4200.

MORE INFORMATION
Microsoft Windows, Version 3.0 Automated Product Support Service Fax-Script Questions and Answers: Using a Modem with Windows 3.0 -

1. Q. I want to use my modem with Windows. Which COM port should I     use?

A. Since there is no single hardware standard for how COM ports 3 and 4 are implemented in various computers, we recommend that you use COM port 1 or 2 for your modem, especially if you are running Windows in 386 enhanced mode.

2. Q. I want to use my modem on COM port 3 or COM port 4. What do I     need to do?

A. Since there are many different hardware configurations for COM ports 3 and 4 on different computers, we cannot guarantee Windows support of these ports. However, if your computer has a     BIOS that supports COM 3 and COM 4, the following information should help you with this setup.

A brief note on COM ports: Unless you are using an EISA or Micro Channel computer, you cannot use COM 1 and COM 3 at the same time. Nor can you use COM 2 and COM 4 at the same time. COM ports 1 and 3 share a single hardware interrupt, as do COM ports 2 and 4. Therefore, if your mouse is installed on COM port 1, COM port 3 will never be available while using Windows.

To configure Windows to support the use of COM ports 3 and 4, edit the SYSTEM.INI file. Start Windows Notepad and open the SYSTEM.INI file. Find the section title line that reads [386Enh]. Below it, enter the following four lines, with no     spaces, and with uppercase and lowercase letters, as shown:

COM1BASE=3F8h COM2BASE=2F8h COM3BASE=3E8h COM4BASE=2E8H

If you have an EISA or Micro Channel computer, add one more line to allow you to use all four COM ports at the same time:

COMIrqSharing=true

Save your revised SYSTEM.INI file and restart Windows. KBCategory: kbother kbfasttip KBSubcategory: win30 Additional reference words: 3.00 3.00a 3.0a 3.0 usage ivrfax QWW30

Last Reviewed: November 23, 1994