Some keyboard controllers' implementation of N-key rollover presents compatibility problems on some non-Windows operating systems, in particular OS X. Noppoo keyboards in particular are known to fail under OS X.
USB to PS/2 to USB
- Connect keyboard to passive USB to PS/2 adapter: this switches the keyboard to PS/2 compatibility mode
- Connect the passive adapter to an active PS/2 to USB converter: this generates a clean USB device free of N-key rollover hacks
Using a Belkin F5U119-series PS/2 to USB converter