Standard Serial over Bluetooth link (COM139) Driver

The Standard Serial over Bluetooth link (COM139) driver lets Windows applications communicate with a paired Bluetooth device through a virtual serial port. Provided by Microsoft as part of compatible Windows Bluetooth support, it is useful when a serial-enabled Bluetooth accessory needs a COM connection rather than a physical cable. COM139 identifies the assigned port, not a unique hardware model, so troubleshooting should also account for your Bluetooth adapter and connected device.

Key Features

• Virtual serial communication: Supports Bluetooth Serial Port Profile connections for compatible accessories and applications that use COM ports.
• Microsoft driver integration: Works with Windows Bluetooth components to expose a serial connection to supported software.
• Application compatibility: Allows programs with serial-port settings to select COM139 when that port is assigned to the intended device.
• Broad Windows coverage: Relevant Windows versions include Windows 10, 8.1, 7, Vista, and XP, although functionality depends on the Bluetooth adapter, its drivers, and the accessory’s supported profiles.

How to Install Standard Serial over Bluetooth link (COM139) Driver

1. Check the existing connection. Open Device Manager and look under Ports (COM & LPT) and the Bluetooth category. Confirm whether COM139 is present and note any warning icons. Although this listing is categorized under USB, the entry represents a virtual Bluetooth serial port; the Bluetooth adapter may connect through USB.

1. Confirm compatibility before downloading. When looking for a Standard Serial over Bluetooth link (COM139) driver download for Windows, check your Windows version and system architecture. Microsoft’s virtual-port support is typically supplied through Windows rather than a separate COM139-specific installer. Avoid unrelated packages advertised as a free download.

1. Install or update Bluetooth support. Run Windows Update, or obtain the correct Bluetooth adapter driver from your computer or adapter manufacturer. On Windows 10/11, available driver updates may appear under optional updates; Windows 11 compatibility should be checked separately.

1. Pair the accessory. Enable Bluetooth, pair your serial-capable device, and configure its serial service if required. Windows may assign a port number other than COM139.

1. Verify operation. Select the assigned COM port in your application, apply the accessory’s required communication settings, and test the connection. Restart Windows if the installation requests it.

Keep the driver and Bluetooth adapter software updated through trusted sources. The latest version appropriate for your hardware and Windows release can help resolve connection issues, but an update is not guaranteed to change the assigned COM number or add unsupported Bluetooth profiles.