The Fujitsu EC (Embedded Controller) Interface Driver is a system driver used in Fujitsu laptops or desktops to manage communication between the system's embedded controller (EC) and other hardware components. The embedded controller is a microcontroller responsible for low-level tasks such as power management, thermal control, battery charging, keyboard input, and other system functions that are handled by the system firmware.

In simpler terms, the EC Interface Driver ensures that the operating system can properly communicate with and utilize the embedded controller on your Fujitsu device. Without the correct driver, certain system functions like power management or hardware button functionality may not work properly.