Name: Keyspan USB 4 Port Serial Adapter (USA49W) Driver
Author: Keyspan

Question 1

Installer fails or hangs?

Accepted Answer

Run the Keyspan USA49W driver installer as Administrator and use Windows compatibility mode for older Windows versions. Temporarily disable antivirus, then reboot before retrying.

Question 2

Adapter not detected?

Accepted Answer

Check the USB cable and try a rear motherboard USB port directly, not a hub. In Device Manager, look under Ports and Universal Serial Bus controllers; if unknown devices appear, uninstall them and rescan for hardware.

Question 3

COM port or driver version conflicts?

Accepted Answer

Remove any older Keyspan/Tripp Lite serial drivers before installing the current USA49W package. In Device Manager, verify each of the four ports has a distinct COM number and update the driver if Windows assigns a generic USB serial driver.