Complete sub-assembly
Provided by the ASK Keyboard Dictionary
Also known as: subassembly, internal keyboard assembly, internal assembly
The complete sub-assembly (CSA) is the name given to a functioning keyboard assembly that can be separated from the keyboard's cover set. "Complete" refers to how such a keyboard assembly also has all the components needs for normal operation (such as keycaps and controller card) connected to it. Model B, Model F, and (most) Model M family keyboards used CSAs.