Fanuc Option PCB for 16i/ 18i/ 21i A20B-8100-0560

📌 FANUC A20B‑8100‑0560 — “CAP‑II” PCB / Option Interface Board

• Part Number: A20B‑8100‑0560

• Description: CAP‑II PCB — a communication/option interface printed circuit board used within FANUC CNC controller units.

• Series: A20B‑8100 family of CNC control PCBs (covers option, communication, and interface boards).

• Function: This board provides an option interface, often related to CNC controller capabilities beyond the core CPU — such as extended communication, specific module support or integration with other controller sub‑systems. The “CAP‑II” designation identifies it as a specific option/communication board type in the series.

• Usage: Installed inside the controller electronics rack/backplane alongside CPU boards, memory modules, display cards, and other option/communication boards. The exact function depends on controller configuration and option selection.

• Application: Common in FANUC Series 16i, 18i, 21i and other system controllers that support modular option cards — this board extends or augments communication/interface capabilities.

• Availability: Often sold new surplus or as refurbished/tested units by industrial parts suppliers. Core exchange may be required with some vendors.