Sierra Wireless AT Command Port (UMTS) (COM4) Driver

The Sierra Wireless AT Command Port (UMTS) (COM4) driver allows Windows software to communicate with the AT-command interface of a compatible Sierra Wireless mobile broadband modem. You may need it if the port appears as an unknown device, modem-management software cannot access it, or you are restoring a computer’s cellular connectivity setup.

Key Features

• AT-command communication: Provides access to a modem’s command interface for compatible utilities that query device information, check connection status, or manage supported settings.
• Serial port recognition: Helps Windows identify the modem’s AT-command port in Device Manager. Although this device name includes COM4, the assigned port number can vary between systems.
• Mobile broadband support: Works as part of the modem’s driver setup; separate modem or network-interface components may also be required for internet access.
• Legacy Windows compatibility: Intended for compatible configurations running Windows 10, 8.1, 7, Vista, or XP. Check the individual package for supported Windows editions and 32-bit or 64-bit architecture.

How to Install Sierra Wireless AT Command Port (UMTS) (COM4) Driver

1. Identify your hardware and Windows version. Open Device Manager, locate the Sierra Wireless port or unidentified device, and check its Hardware IDs under Properties > Details. Confirm your Windows version and system architecture before selecting a package.
2. Choose a matching package. Before starting your Sierra Wireless AT Command Port (UMTS) (COM4) driver download for Windows, verify that the package supports your modem model. Prefer a trusted manufacturer or computer-maker source when selecting a free download.
3. Prepare the files. Extract the downloaded archive if needed. If you are replacing a working driver, consider creating a restore point first.
4. Install the driver. Run the included installer and follow its instructions. If the package provides driver files without an installer, open Device Manager, right-click the device, select Update driver, and browse to the extracted folder.
5. Verify recognition. Restart if prompted, then confirm that the port appears without a warning icon. Configure your modem utility to use the assigned COM port rather than assuming it is always COM4.

Keep the driver updated when a compatible release addresses connection problems or improves stability. Choose the latest version approved for your specific modem, not simply the newest package available. For Windows 10/11 systems, check support separately: Windows 10 compatibility does not establish Windows 11 support. Before any update, retain the previous installer in case you need to roll back.