Windows driver issues

You see

You plug your laser into a Windows machine. Beam Bench's port dropdown does not show the machine. Device Manager may show "Unknown device" or "USB Serial" with a yellow warning triangle.

What is happening

Most diode and small CO2 lasers use a USB-serial adapter chip inside the controller. Windows does not ship drivers for all chips. Without a driver, Windows cannot recognize the port, and Beam Bench cannot see it.

The two most common chips are:

• CH340 (WCH brand), common on entry-level diode lasers.
• CP210x (Silicon Labs), common on slightly more expensive or CO2 machines.
• FTDI chips also exist but Windows usually has the driver built in.

Fix

Identify the chip

Open Device Manager:

1. Start menu → "Device Manager".
2. Look for Ports (COM & LPT). If empty or your device is missing, look under Other devices for an unknown one with a warning.
3. Right-click the device → Properties → Details tab → set Property to Hardware Ids.
4. The vendor ID (VID) and product ID (PID) tell you the chip:
   • VID_1A86 = CH340.
   • VID_10C4 = CP210x.
   • VID_0403 = FTDI.

Install the CH340 driver

Search "CH340 driver Windows", first result from WCH or a reputable mirror.

1. Download the installer.
2. Run as Administrator.
3. Unplug the laser if connected.
4. Install.
5. Plug the laser back in.
6. The port should appear in Device Manager → Ports as USB-SERIAL CH340 (COMx).

Install the CP210x driver

Silicon Labs's "CP210x VCP Driver". Search "Silicon Labs CP210x VCP driver Windows". Same steps.

After installing

Open Beam Bench's Connection dropdown. The port (COM3, COM4, etc.) should be listed. Connect.

If the device still does not show up

• Try a different USB cable.
• Try a different USB port (avoid hubs).
• Some chips need a specific driver version, check the laser manufacturer's website for what they ship with.
• A few cheap controllers use unofficial USB chips that even WCH's driver does not recognize. In that case, the controller manufacturer's documentation should specify a driver.

Verify it worked

• Device Manager → Ports shows your serial chip with a COM number.
• Beam Bench's Connection dropdown lists the same COM number.
• You can connect and see the GRBL welcome message in the Console.

Still stuck?

• Port is not listed.
• Baud rate and serial port guide.
• Post in the Facebook group with the Windows version and the laser controller model.