how to hack samsung MWR-SH00N cable remote controller


At the office we are using samsung central air conditioning system, by default it doesn't have auto start option on the remote controller(it has shutdown timer tho), what i want to do is start air conditioner with arduino with using time module at desired hour.

Remote controller of the AC is this :

It's working with cable (if it was infrared then it would be easy pie but nothing is easy in my life)

So i dismounted the remote controller and dis-assembled to see how it works, here is the belly of the beast

so, usually remote controllers using short to understand which button is pressed, i mean silicon buttons in remote controllers are conductive when you press the button it's shorting the button's circuit and the chip knows which button is shorted/pressed, you can hack this logic with arduino and simulate the button press.

But at this remote when i short the button's GND and + nothing happens (i've another remote controller for testing stuff, when i short for example power button on it it works, but on this remote it doesn't work)

I thought maybe it's sending voltage through power supply cables at the bottom and tried to measure voltage changes when any button pressed -- no luck it allways gives 12V constant.

I thought maybe it's sending ohm when button pressed but no luck either.

Only amp is changing when you pressing the button but as far as i know buttons consumes power too and it's causing that amp changes.

I need to interrupt power button with arduino so i can shutdown or start AC automatically any time i want.

I'm pretty sure that it works as the same way as IR remotes but the only difference is this one works with cable, and somehow it's relaying commands through power supply cables, i need to find how it does it?

Any ideas?