The Fanuc 9900 series parameters are critical system-level settings used primarily in newer Fanuc controls (such as the 0i, 16i, 18i, and 21i series) to define machine configuration and unlock optional software features.
Fanuc intentionally restricts access to parameters 9900–9999. On most controls (Series 0i, 15i, 18i, 21i, 30i, 31i, 32i, and 35i), you must: fanuc 9900 parameter list
Fanuc considers the 9900 range to be proprietary information. Accessing or modifying these often requires specific conditions: fanuc parameter detail 9900 to 9998 | Practical Machinist The Fanuc 9900 series parameters are critical system-level