The 900 parameters are essentially the "firmware" settings of your lathe. While it's tempting to "turn everything on," incorrect settings can cause system crashes or render the machine unresponsive. before making changes, as many older 0-T controls do not have a "factory reset" button that restores these specific bits. Fanuc Ot 900 Parameter List - Google Groups
The on the Fanuc 0-T control are "option parameters" that enable or disable specific hardware and software features. Each parameter number (e.g., 900, 901) consists of 8 bits (labeled 0 through 7), where setting a bit to "1" activates a function and "0" deactivates it. Key 900-Series Parameter Bit Definitions fanuc ot 900 parameter list
When standard troubleshooting fails, the becomes your most powerful diagnostic tool. The 900 parameters are essentially the "firmware" settings