In the very near future I will have all the parts to build a Mendel. I wanted to build the Mendel first since it is VERY well documented, anyways I just received the electronics from Makerbot, and i am reading about the modifications needed to make it reprap compatible. My question is why am i removing the ethernet ports? Why not just use them? Is there a problem using ethernet cable to connect things? If there is nothing wrong with the cable then i will just use them. Someone please let me know if it matters... thanks https://reprap.org/forum/read.php?13,45464,45464#msg-45464 Thu, 11 Jun 2026 18:33:57 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?13,45464,46418#msg-46418 https://reprap.org/forum/read.php?13,45464,46418#msg-46418 Matthew Controllers Tue, 25 May 2010 10:07:07 -0400 https://reprap.org/forum/read.php?13,45464,45568#msg-45568 https://reprap.org/forum/read.php?13,45464,45568#msg-45568
The signals on the stepper motor controller really isn't a good match for this. The signals are single-ended and don't have matched termination impedances. Taking two single ended signals and twisting them together for the length of a cable increases the coupling between these signals which increases interference and decreases signal integrity. This is really opposite the purpose of differential signals and use of twisted pair cabling. However, this doesn't mean it won't work. It just isn't optimal.

Note that one could take untwisted cable and terminate it with RJ-45 connectors to avoid the increased coupling due to the twisted pairs of CAT-5e cables.

Note also that the flat ribbon cables are also not ideal. Wires are held in close proximity for the length of the cable which also results in coupling between the signals. If one were concerned about signal integrity with single ended signals run through ribbon cables then it is common to allocate pins such that every other wire is a ground (signal, ground, signal, ground, etc.). However this isn't possible either given the current connectors/cables.

So, sorry to say, that from a signal integrity point of view there isn't a clear winner either way. If it works (and it clearly does for many)... live with it. But this is something that can, and should be, improved in future iterations (in my opinion).

TC]]> TC Controllers Fri, 14 May 2010 23:40:30 -0400 https://reprap.org/forum/read.php?13,45464,45535#msg-45535 https://reprap.org/forum/read.php?13,45464,45535#msg-45535
Using a swap over cable has been reported to kill the opto endstops.]]> freds Controllers Fri, 14 May 2010 14:14:06 -0400 https://reprap.org/forum/read.php?13,45464,45533#msg-45533 https://reprap.org/forum/read.php?13,45464,45533#msg-45533 -------------------------------------------------------
> I haven't finished mine yet, but I don't think
> there's any technical reason to do the
> modifications. Those changes are basically just
> to make it a lot easier and cleaner since the
> ethernet cables are kind of bulky and difficult to
> plug in.


ok thats what i thought, i was just worried the wire might be too thin or something like that]]> fairchild Controllers Fri, 14 May 2010 14:12:16 -0400 https://reprap.org/forum/read.php?13,45464,45521#msg-45521 https://reprap.org/forum/read.php?13,45464,45521#msg-45521 gr0k Controllers Fri, 14 May 2010 12:11:54 -0400 https://reprap.org/forum/read.php?13,45464,45464#msg-45464 https://reprap.org/forum/read.php?13,45464,45464#msg-45464
My question is why am i removing the ethernet ports? Why not just use them? Is there a problem using ethernet cable to connect things? If there is nothing wrong with the cable then i will just use them.

Someone please let me know if it matters... thanks]]> fairchild Controllers Thu, 13 May 2010 21:53:48 -0400