Finally connected it to Gpredict and works on the first try, lol. Well mostly because I was helped by my friend who build his own rotator in the past, so working well so far.
Also, I tried using this USB to ethernet and works well for at least 10m of Cat6 ethernet cable. How did you plan to control yours? I might just put a Raspberry Pi beside the Arduino on the rotator and SSH the Raspberry Pi.