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HOW TO DETERMINE IF YOU HAVE A HARDWARE CONFLICT

The most common configuration of Com Ports for computers is a Serial I/O card set to Com 1 and Com 2. If you install your Internal Modem to the factory default of Com 2, YOU WILL HAVE A HARDWARE CONFLICT!

Before installing the modem into your computer it is a good idea to determine what serial ports are installed in your computer... if any. You may assume that you have only Com 1 on your computer, when you actually have both Com 1 and Com 2. You also might have many other combinations of Com Ports.

Most computers have a Serial I/O (Input/Output) card installed with Com Ports 1 and 2 enabled. These cards allow you to connect with external modems and a mouse... just to name a couple. Even if you don't have any thing connected to the RS232 jack on the I/O card, it is still using a Com Port. A Com Port may only be used by one device.

Many problems you may experience are caused by configuring the modems Com Port to a port already installed in your computer system. One symptom of this conflict is the modems inability to dial or respond to a command. Windows 95 may not even start or start in the safe mode! Hardware conflicts can also cause very strange and intermittent problems such as working one day and not the next, or garbage displayed when connecting to another modem, or working as a fax and not as a modem, or visa versa.

To alleviate this conflict you must first determine which Com Ports are available and which Com Ports are already being used.

Recalling that each Com Port has a specific address assigned to it, we can use a diagnostic abilities built into Windows 95. To do this, follow the instructions below:

Determining What Serial Ports Are Installed In Your Computer

  1. Start the Win95 Control Panel
  2. Double click on "System"
  3. Click on the "Device Manager" tab
  4. If View devices by type does not have a check mark next to it, click on the box to check it off.
  5. Double Click on "Computer" to display system resource information.
  6. Ensure that IRQ is selected and view the available IRQ's
  7. Click on Input/output to view the port address used on the system.
  8. If a port exists when the internal modem is not installed in the system, you CANNOT install the internal modem set to that port. If the IRQ was used by another device you also cannot select that IRQ.

Since most system already have Com 1 and Com 2, a good choice would be COM3 or COM4. The IRQ you select is another matter. Beware of using COM4 if your video card uses a graphics card with the S3 chip. It has been know to interfere with modems operating on COM4. Updated video drivers have apparently solved this problem.

Example troubleshooting

If you already installed a modem, lets say on Com 2/IRQ 3 and don't know if Com 2 already existed before installing the modem, use the following procedure to determine this in Win95. If your internal modem is set to another port, just substitute your port with the Com 2 mentioned below.

  1. Remove the internal modem, set to COM2/IRQ 3, from the computer. (Make sure the power is off)
  2. Start Windows 95.
  3. Start the Win95 Control Panel
  4. Double click on "System"
  5. Click on the "Device Manager" tab
  6. If View devices by type does not have a check mark next to it, click on the box to check it off.
  7. Double Click on "Ports" to display system resource information.
  8. Click on "Communications Port (COM2)" to highlight it.
  9. Click on the Remove button.
  10. When prompted to confirm your choice, click on the "OK" button and exit the System configuration.
  11. Click on "Add New Hardware"  in the Control Panel.
  12. Let Windows 95 automatically detect the new hardware. (You will be warned that the process may take a while)

If Windows 95 detects a COM2 when the modem is removed, you have discovered the problem. Your system already has a COM2. You must remove the device set to COM2 or disable the motherboards onboard COM2. This is usually done in the BIOS setup screens. Refer to your motherboard manual for information on disabling the onboard communication ports.

If Windows 95 does not detect a COM2 when the modem is removed, you should be able to set the modem to COM2 without any conflicts. Just remember to let Windows 95 find the new port after installing the internal modem.

Copyright@1996 Zoltrix Inc.
Last updated on January 7, 1998.