its powered by 24v but it has 5v inputs and outputs. Some motor drives require resistor even for the 5v step dir signal, so read your motor drive manual.

I did not require much, just to work, which it did not. Apart from basic functions like moving the motors, which the board did right, i had non working PWM output, relay switching on and off when it wants to, output voltage for VFD was not stable, manual was well written at times, at times missing important info, etc.

Maybe i had some bad interference problems from my servo drives. Or faulty board, which i doubt as i had similar problems from other board on its place, so the interference problems may be the explanation. Support was ok, they answered my questions and tried to help me. We had long conversations. In short- i wanted this combo to work- it did not. I dont say its good or bad, it did not work for me. That's all.

Its not so cheap as it looks on first glance. if i were you i would go with the one Dean recommends so much - the CSMIO 4 axis. A bit more expensive but really much more professional. It is tested with time, 24V IO, differential IO and most of all is properly shielded. The chinese offline controller DDSCV1 also works for the moment ok.

Limit switches can work on 24v and using a resistor be connected to the 5v input of any board. So no, that's not the deal. The deal is the 24v IO of the board, that will not show false positive to say, when some spikes arise. As happened with the Pokeys. It was funny to try to probe with it and every couple of seconds the led will light and the board will think that the probe was triggered. Falsely of course. So no probing working properly. That could not have happened with 24v signal. I would say even the bigger deal is the differential signals to motors but you need good drives that support that.