The Fanuc A20B-3900-0183 is a high-capacity combined memory module designed for Fanuc Series 16i/18i/21i Model B and compatible CNC systems. This plug-in daughter board integrates 32MB FROM (Flash ROM) for non-volatile system software, part programs, and parameter storage with 512K battery-backed SRAM for real-time data retention and machining information during power loss. It features industrial-grade memory chips, robust edge connectors for direct main board integration, and low-power CMOS circuitry operating on system-supplied voltages. [stock available]