The FANUC A16B-2201-0721 is an industrial Main CPU Board (Master PCB) engineered for FANUC Series 20 and 21 CNC architectures (such as the FS-20/21 model lineages). Acting as the primary processing core for the controller rack, this multi-layer circuit board manages high-speed system trajectory calculations and master logic routing. The PCB is built as a highly customizable hardware host, featuring six dedicated plug-in surface-mount device (SMD) expansion slots designed to accept various auxiliary modules, including SRAM/FROM system memory cards, digital/analog axis interfaces, serial spindle controllers, and graphics sub-boards. [stock available]