Can I use Cat cable to control this via switch from 50metres away?
The product can be remotely controlled in two ways.
I would not.
The loop distance is ~100m, and cat cables are not designed to carry power. This remote switch caries the power for the control board. I would use 2 strands of 19/0.2* (3A flex) or larger to do this.
19/0.2 = 19 strands of 0.2mm diameter tinned copper wire.
Okay, do you know how many Volts is on that circuit? There is no answer in manual.
-CAT cables are used to send PoE-power via pins 4, 5, 7 & 8. Networking uses only 4 pins.
Power over Ethernet (PoE) delivers power over standard Ethernet cables, typically at a voltage between 44 and 57 volts DC, with 48 volts DC being the most common standard.
The answer could be a lot easier if someone will take out the “short” in the Remote On/Off connector and put there a multimeter set for measuring currents. Based on the current measured there, you can use the corresponding wire.
I have the feeling, but I may be wrong, that it’s a digital input type, with less than 10mA.
I will do this after weekend. Will share info here.
@Alpobass
So?.. 
So, I tried with Fluke meter. At start 0,10mA and after running a while 0,02mA. Made connection with CAT-cable, one pair to and from (two wires together). Works absolutely fine from 50 metres.
Thank you for the info! 
So, with under 1mA current, this confirms that it could be a digital like input, regardless of logic voltage.
