The FANUC A20B-2101-004 is a high-performance control board designed for FANUC Alpha and Alpha i series servo amplifier modules. This essential component serves as the central processing unit for the servo drive, managing communication, processing feedback, and controlling motor operations within a CNC system. It features dual optical fiber interfaces (COP10A/COP10B) for high-speed FSSB (Fanuc Serial Servo Bus) communication, ensuring precise and synchronized control of servo axes. Equipped with power connectors CXA2A and CXA2B, an encoder feedback port (JF1/ENC1), and a battery holder for memory backup, this board is engineered for reliability and seamless integration into industrial automation environments. Status LEDs provide at-a-glance diagnostics for simplified troubleshooting and maintenance.