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How do I change the COM port setting for my 3Com PCI 56K modem? - Technical Tip - 135145

Edit the Registry to Modify the COM Port Setting

NOTICE: The following procedure contains information about editing the Windows registry. Dell does not guarantee success or support these actions. Any use of the information provided herein, is performed at your own risk. You should make a backup copy of the registry files prior to executing any of the following steps. Incorrect use of the registry editor and editing the registry files can cause serious problems that may require a complete reinstall of your operating system. Dell assumes no responsibility, expressed or implied, regarding the consequences of any action taken as a result of the information provided herein.

To change the COM port setting for the 3Com® PCI 56K modem, modify the registry:

  1. Click the Start button, click Run, and then type regedit in the Open box. Click OK.
    The Registry Editor window appears.
  2. Click Edit and then click Find.
    The Find window appears.
  3. In the Find what: field, type PORTNAME and click Find Next.

    NOTE: The registry path will vary depending on the way the software was downloaded to the system at the factory.

    HKEY_LOCAL_MACHINE\Enum\PCI\VEN_12B9&DEV_1008\xxxxxx\PORTNAME (where xxxxxx is the memory address for the PCI slot in which the modem installed) appears.
  4. Double-click PORTNAME and in the dialog box change COM5 to COM3 (or the desired COM port).
  5. Click the plus (+) sign next to each of the following keys:

  6. Click CommAlias to highlight the folder.
  7. Click Edit and then click Delete.
    The Confirm Key Delete window appears.
  8. Click Yes to confirm deletion.
  9. Click the Start button, click Shut Down, click Restart, and then click OK.

Before performing the steps below, try setting the communication software to COM 3.

This article describes how to change the COM port setting for 3Com PCI 56K modems (Controller based modem). Currently, neither the 3Com control panel nor the modem icon within the Microsoft® Windows® Control Panel provide a way to change the COM port setting. As long as the IRQ used by the modem does not conflict with another device, you should not need to change the IRQ. Even though IRQs were once hard-coded to certain COM ports with legacy ISA modems, they are no longer. You may need to change the COM port setting when a communication program is unable to address the modem on what used to be a non-standard port, such as COM 5. Before performing the steps below, try setting the communication software to COM 3. If this does not help, then try the below procedure to change the COM port in the registry.

Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

Article ID: SLN66869

Last Date Modified: 07/31/2010 12:00 AM

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