If you only need basic "graceful shutdown" without advanced settings, Windows 10 and 11 often recognize the APC 420 as a "HID UPS Battery". If the driver doesn't load automatically, you can manually update it via the Device Manager under the Batteries section. Critical Hardware Requirement
You must use an official (Smart Signalling) or 940-0128 cable. If your computer lacks a serial port, a high-quality USB-to-Serial adapter is required to bridge the connection. Installation & Configuration Steps apc smart ups 420 software download
Connect the APC-specific serial cable to the UPS and your PC. Download: Get the PowerChute Serial Shutdown installer. If you only need basic "graceful shutdown" without