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How do I change my COM port Settings?

How do I change my COM port Settings?

When it comes to computer peripherals, managing communication ports—specifically COM ports—is vital for devices like modems, mouses, and printers to interact with your Windows operating system. For enthusiasts and professionals who often need to configure serial devices, changing COM port settings is a routine task. This comprehensive how-to guide will share with you the methods I’ve used to manage COM ports, letting you optimize your setup, troubleshoot issues, or free up port assignments in Windows.


Common Scenarios:

Outdated Device Drivers 💻

  • Encountering issues with device connectivity could potentially be due to outdated or corrupted device drivers.
  • Altering COM port settings might be necessary to resolve conflicts arising from driver updates.
  • Serial device performance can be improved by ensuring drivers are configured correctly with the proper COM port.

Device Conflicts ⚠

  • Changing COM port settings helps resolve device conflicts caused by multiple devices sharing the same COM port.
  • Some devices may not function properly if they are not associated with specific COM ports that their software expects.
  • It’s advantageous to customize COM port numbers to create a more organized and predictable port allocation setup.

Software Requirements 📱

  • Software applications may require dedicated COM port numbers for effective communication with the serial devices.
  • Changing a COM port number could help maintain system compatibility and interoperability with legacy software that is hard-coded to specific ports.
  • Some specialized software tools demand exclusive access to certain COM port numbers, necessitating adjustments in Windows.

Step-by-Step Guide. Virtual Serial Port, Virtual Com Port, Com Port Settings:

Method 1: Using Device Manager 🔧

  • Click on the Start button and type ‘Device Manager’ in the search bar, then open it.
  • Expand the ‘Ports (COM & LPT)’ section to see the list of COM ports currently in use.
  • Right-click on the COM port you wish to change and select ‘Properties’.
  • Go to the ‘Port Settings’ tab and click on the ‘Advanced…’ button.
  • In the Advanced Settings window, use the drop-down menu to select a new COM port number, then click ‘OK’.

Note: Ensure that the new COM port number you select is not currently in use by another device.

Conclusion: This method provides a quick way to change COM port settings and is typically the first step in troubleshooting connectivity issues.

Method 2: Through Registry Editor 🔏

  • Press ‘Windows Key + R’, type ‘regedit’, and press ‘Enter’ to open Registry Editor.
  • Navigate to ‘HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlCOM Name Arbiter’.
  • Make sure to back up the registry before making any changes.
  • Inside ‘COM Name Arbiter’, locate and modify the ComDB value to reflect the desired COM port assignments.
  • Restart your computer for the changes to take effect.

Note: Editing the registry incorrectly can cause serious system issues. Only proceed if you are comfortable with the Windows Registry.

Conclusion: This method should be used with caution and is aimed at experienced users who need to change COM port assignments not available through Device Manager.

Method 3: Using PowerShell ⚡

  • Right-click on the Start button and select ‘Windows PowerShell (Admin)’.
  • Type the following command to list COM port information: ‘Get-WMIObject Win32_SerialPort’.
  • Identify the COM port you want to change from the list.
  • Use commands like ‘New-ItemProperty’ and ‘Set-ItemProperty’ to adjust COM port settings accordingly.
  • Reboot your system to apply the changes.

Note: PowerShell commands must be used with precision, as they act directly on system configuration.

Conclusion: This method is suitable for IT professionals and power users who are familiar with command-line interfaces and PowerShell scripting.

Method 4: Utilizing Third-Party Software 🎮

  • Download and install a reliable third-party COM port configuration tool from a trusted source.
  • Launch the software and follow the on-screen instructions to change COM port settings.
  • Save and apply the changes made using the tool.
  • Restart your device to ensure that the new settings are active.

Note: Research and select third-party software with positive reviews and a track record of reliability.

Conclusion: Third-party tools are convenient for those who prefer a user-friendly graphical interface and additional features not offered by Windows’ built-in tools.

Method 5: BIOS or UEFI Settings 🛠

  • Restart your computer and enter the BIOS or UEFI settings during startup (typically by pressing F2, Del, or another specific key).
  • Look for a section related to Peripheral Configuration or Integrated Peripherals.
  • Change the COM port settings within the BIOS/UEFI if such an option is available.
  • Save your settings and exit the BIOS/UEFI setup.
  • The computer will reboot with the new COM port settings applied.

Note: Not all systems will offer COM port configurations in BIOS/UEFI, and these options vary widely by motherboard manufacturer and model.

Conclusion: Modifying COM port settings at the BIOS/UEFI level can be helpful for ensuring compatibility at boot time and is generally a task for advanced users.


Precautions and Tips:

Essential Precautions ⚠

  • Always back up your system before making changes to COM port settings, especially when editing the registry or BIOS.
  • Check device manuals or support resources for any specific COM port requirements.
  • Be cautious about changing COM port numbers to those commonly reserved for hardware or system purposes, such as COM1 or COM2.

Avoiding Common Pitfalls 😵

  • Confirm that you have administrative rights on your computer to make COM port changes.
  • Make sure to select a COM port number not in use to prevent conflicts.
  • Do not use COM port numbers above COM9 without ensuring your software can handle such assignments.

Further Understanding COM Ports

Computer Operating system Memory ports, or COM ports, are a type of serial interface standards that were originally designed for serial communications between a computer and its peripherals. Despite being a legacy technology, they are still widely used, particularly in industrial and networking applications that require simple, direct serial data connections.

To learn more about serial communication and COM ports, visit the National Instruments serial communication guide. This resource can provide insights into how devices communicate over serial ports and relevant industry standards.

For a deeper understanding of Windows COM port internals and programming, the Microsoft COM Documentation is a valuable repository of knowledge that covers everything from simple configurations to advanced development topics around COM objects and services.


Changing COM port settings can be an integral part of managing your device’s connectivity with your Windows operating system. The methods described above are what I have personally used and found to be effective in various scenarios. Whether you’re troubleshooting a problematic device, setting up a new system, or just reorganizing your device’s ports, these steps can help you to efficiently manage your COM ports. For any changes that you make, remember to proceed carefully and verify your alterations to avoid any potential system conflicts or issues.

By understanding how to configure COM port settings, you can ensure that your devices communicate effectively and maintain a smoothly operating system. Knowledge of COM ports and how to manage them is a valuable skill in today’s tech environment, where serial communication still plays a crucial role in many applications.


A virtual serial port emulates a real serial port connection in software, providing the same communication interface without the need for additional hardware.

A virtual COM port can be crucial for devices that require serial communication but lack physical COM ports, like newer laptops and tablets.

Yes, you can create and manage multiple virtual COM ports simultaneously on a single computer to interface with various serial applications.

Typical COM port settings include baud rate, parity, data bits, stop bits, and flow control, which ensure proper communication.

You modify COM port settings in the software application that created the virtual serial port, adjusting parameters as needed.

Virtual serial ports allow developers to simulate and test serial device communications without needing actual hardware, saving time and resources.

Yes, you can connect two virtual serial ports in a pair to form a virtual null modem connection, enabling two apps to communicate locally.

Applications such as serial port monitors, telecommunication software, and development tools for embedded systems often need virtual COM ports.

Virtual serial ports work independently of the OS architecture but require compatible virtual port driver software.

You can find virtual serial port creation software on websites like Eltima Software or Virtual Serial Port, which offer specialized solutions.