Question 1

Device not detected / no COM port?

Accepted Answer

Check Device Manager for an unknown device or warning under Ports (COM & LPT). Try a different USB port and cable, avoid unpowered hubs, then uninstall the device and rescan.

Question 2

Install fails or driver won’t load?

Accepted Answer

Run the OTI installer as administrator in Windows compatibility mode. If Windows blocks the driver, temporarily disable driver signature enforcement or use a signed package, then reboot.

Question 3

Version or COM-port conflicts?

Accepted Answer

Uninstall older OTI/USB-serial drivers and select “Delete driver software,” reboot, and install only one version. If an app cannot open the port, change the assigned COM number in Port Properties and close other serial programs.

OTI USB to Serial Comm Port Driver