DMX is a 3-wire signal and those three labels sound correct. We often use Cat5 cables to carry the DMX signal but when doing so, only three of the cores are in use. The Din and Dout are probably connected in parallel to each other. If so then they are electrically equivalent. You could check with a multimeter. It is common practice to daisy chain DMX devices using connections like this. There is a thread here which is for a DMX controller and it includes instructions for how to add RJ45 plugs for the DMX signal. The only difference is that there is only one set of solder pads on this controller but yours has two sets. If you want to copy this exactly, you can choose to either use the Din or the Dout. For simplicity, I would solder one RJ45 plug to the Din and one to the Dout.
I am of course making some assumptions here and I have never seen the DMX device that you're referring to. The problem with using DMX for pixels is that it is limited to 512 channels and these are quickly used up. Setting the start channel is also another unanswered question.
I am of course making some assumptions here and I have never seen the DMX device that you're referring to. The problem with using DMX for pixels is that it is limited to 512 channels and these are quickly used up. Setting the start channel is also another unanswered question.