This parameter is unique. Instead of individual bit functions, Fanuc often encoded a checksum or a software option key here. Changing 909 requires a specific 8-digit code from Fanuc. Do not modify unless you have a purchased option key.
Backup and recovery
Canned Cycles (bit 0), G10 Input (bit 1), Inch/Metric (bit 5). 901: Chamfering (bit 5), G70-G76 Cycles (bit 7). fanuc ot 900 parameter list
Each parameter 900–909 is usually written in or decimal value derived from bits. This parameter is unique