I have posted a few previous outlines on the Fanuc encoder, the last three numbers tell what type encoder, absolute or incremental/differential.
The C1-C8 is the proprietary commutation code for the AC servo motor.
There is a member here that has built a circuit mod for the commutation to standard BLDC.
You should find the PDF posted previously on the commutation pattern.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.