Standard Serial over Bluetooth link (COM31) Driver

The Standard Serial over Bluetooth link (COM31) driver lets Windows applications communicate with a paired Bluetooth device through a virtual serial port. Associated with Microsoft’s Bluetooth support, this component is useful when a serial-enabled Bluetooth accessory needs a COM connection rather than a cable. COM31 is the port number assigned on your computer, not a separate hardware model.

Key Features

• Virtual serial communication: Provides a COM-port interface for compatible Bluetooth devices that support the Serial Port Profile (SPP).
• Application compatibility: Lets software that uses serial connections access a paired Bluetooth accessory by selecting its assigned port.
• Windows integration: Works with Windows Bluetooth services and a compatible Bluetooth adapter driver to establish serial connections.
• Device Manager visibility: Makes the virtual port available for checking device status, troubleshooting connection issues, and managing driver updates.

How to Install Standard Serial over Bluetooth link (COM31) Driver

1. Check your Windows version and adapter. The listed operating systems are Windows 10, 8.1, 7, Vista, and XP. Confirm your Bluetooth adapter supports your system and check whether Windows is 32-bit or 64-bit before choosing any package. For Windows 10/11 searches, note that Windows 11 is not included in this page’s stated support list.

1. Choose a trusted driver source. Before starting a Standard Serial over Bluetooth link (COM31) driver download for Windows, check Windows Update or your PC manufacturer’s support resources. Microsoft’s virtual serial-port component is typically supplied with Windows; a separate free download may not be necessary.

1. Install or update Bluetooth support. Install the appropriate Bluetooth adapter driver if it is missing or malfunctioning. Restart your computer if prompted, then enable Bluetooth.

1. Pair your serial-enabled device. Add the accessory through Windows Bluetooth settings and follow its pairing instructions. Depending on the device and Windows version, you may need to configure a Bluetooth COM port manually.

1. Verify the port and test the connection. Open Device Manager and check under Ports (COM & LPT) for the Bluetooth serial entry. Select COM31 in your application only if that is the assigned port; Windows may allocate a different number.

Keep Bluetooth support updated through trusted sources, especially if pairing fails or the virtual port disappears. The latest version should match your operating system and adapter—not simply carry a newer label. Before you update a working setup, check the release notes and retain your current connection settings.

Common Issues and Fixes

• COM31 not detected after pairing: The Bluetooth serial service may not be enabled. Remove the device in Bluetooth settings, re-pair it, and enable the “Serial Port”/SPP service if shown. Check Device Manager under Ports (COM & LPT) and scan for hardware changes.
• Install fails or driver conflicts: This device usually uses Microsoft’s inbox Bluetooth serial driver. Uninstall any old OEM Bluetooth/serial driver, update the Bluetooth adapter driver, then in Device Manager uninstall the COM31 device and rescan.
• COM31 cannot be opened or wrong port: Another app may be using the port, or the app is configured for a different COM number. Close conflicting software, verify the assigned port in Device Manager, and select COM31 in the application’s serial settings.