The SW900 has the same connector wiring as a KT display. I presume an S900 does too. I had an S866 that works with Brainpower controllers, and it has the same wiring as a KT. I've mixed the displays and controllers together when I had them.
All will connect to battery power/ground on the red/black. and allow the display to be turned on. That raises the blue wire to battery, which powers up the controller. Then the green/yellow data wires start trying to talk, but cannot, and we may get a COMM error.
The fun part is that KT displays can work without a display, so if a foreign display is connected, you still get throttle and a default PAS. That really confuses people who have attached an SW900. Meanwhile, some other non-KT controllers can do the same, and that confuses someone who has plugged in an LCD3.