Obtain the latest version (v3.8.19.1 or newer) from the Microsoft Update Catalog or the manufacturer's provided link.

3.8.19.1 (Latest stable release for most Z-TEK models) Release Date: January 19, 2018

If your software requires a specific port (e.g., COM1), you can change this in Device Manager > Port Settings > Advanced . Remember to restart your computer for the change to take full effect. Driver Specifications