A20B-3900-0165 FANUC FROM/SRAM Memory Module RJ31B

The A20B-3900-0165 is a FANUC PC card / memory module, commonly described as a FROM/SRAM memory module RJ31B. It is used in compatible FANUC CNC control systems for memory-related functions, system data storage, SRAM data support, and CNC operation depending on the original system configuration.

This model is supplied as a FANUC PC card / FROM SRAM memory module, not a complete CNC control system. It is also listed as discontinued by manufacturer and replaced by A17B-3900-0125, so stock availability and replacement compatibility should be confirmed before ordering.

Worldwide Shipping & REACO CNC Service

• Worldwide Shipping: We can ship worldwide by DHL, UPS, FedEx, or other available logistics channels.
• Fast Handling: In-stock items can usually be shipped within 1-2 working days after payment.
• 100% Tested Before Delivery: Each qualified memory module is tested or checked before shipment. Product photos or a test video can be sent before delivery when required.
• REACO Warranty: New or refurbished products usually include a 1-year warranty, and used 90% new products usually include a 3-month warranty.
• Free Technical Support: Our team can help with basic model confirmation, memory module matching, and replacement guidance.

Product Information

Product Application

The FANUC A20B-3900-0165 memory module is mainly used for compatible FANUC CNC control system repair and maintenance. It may be required when the original memory module is damaged, unstable, missing, or causing CNC boot, system memory, SRAM, data storage, or operation-related problems.

Because this is a memory-related CNC component, replacement should be handled carefully. Before replacement, please confirm the original module number, CNC system model, memory configuration, SRAM data backup status, and system compatibility.

Replacement Note

The A20B-3900-0165 is listed as discontinued by manufacturer and replaced by A17B-3900-0125. Before using the replacement model, please confirm the original memory module, CNC system configuration, software version, SRAM requirement, and machine data backup status.

Although replacement models are often used for maintenance purposes, compatibility should still be checked carefully according to the actual FANUC CNC system and machine configuration.

Quality Control and Testing

For FANUC FROM/SRAM memory modules, careful checking is very important before shipment because memory module condition may directly affect CNC startup, system data storage, parameter retention, SRAM data, and machine operation. REACO CNC checks qualified products carefully and can provide real product photos or a test video before delivery when required.

Our goal is to help customers receive reliable FANUC CNC spare parts with clear product information, careful inspection, responsive after-sales support, and practical technical assistance.

Compatibility Confirmation

Before ordering, please confirm that the full module number on your original memory module is A20B-3900-0165, or that your system supports the replacement model A17B-3900-0125. Similar FANUC memory modules may have different capacities, hardware versions, SRAM configurations, CNC system compatibility, or software requirements.

Please back up your machine data before replacing memory-related CNC components, including parameters, programs, PMC ladder, macro variables, pitch compensation data, and SRAM data if applicable. If you are not sure whether this FANUC FROM/SRAM memory module is suitable for your machine, please send photos of the original module label, CNC system model, CPU board model, software version if available, and alarm information. REACO CNC can help check the details before purchase.