Passive Hub - Probably a stupid question....

[cpnbnanamn]

So..  I think I've asked this question before..  but I want to verify it...  (I can't remember the answer, nor find out where I asked it)...  Will the Passive hub work with other devices BESIDES the SSC's?  For example, LE's?  I've been looking for the answer, but can't find a clear one.  Anyone?

[scharbon]

No, The passive hub will only work with SSCs.

If you have an active hub, it will split out a DMX signal (which the LE's run off of).

You will also need a dongle of some sort (DMX dongle if only working with LEs or other DMX devices; Pixelnet dongle or Etd if any SSC/DSC are in the mix).

If you are still confused, tell us what you have controller wise and we can tell you what you need/are missing.

Steve

[twooly]

Nope it will not, the passive up only has pixelnet outputs for the SSC/DSC.  The Active Hub does have the DMX out for the LE to get a signal from.

[cpnbnanamn]

Crap.  And I need that hub.  Thanks, guys!

I'm doing a small show this year..  Just 2 LE's.  Nothing fancy.  Haven't had the heart the past couple of years.  Almost sold all my stuff and got completely out.  Probably too late to get an active hub now anyway.

[arw01]

If you are ONLY using LE's and you have a USB dongle you can flash that to DMX and use that with the computer and a few cables to run both the LE's.  The LE's have two DMX ports.

Alan

[cpnbnanamn]

I've got the USB dongle that is already flashed for DMX...  Been using it with my controllers.  Problem is, the LE's are on opposite sides of the house, and a splitter would have been PERFECT...  Didn't want to have to zig-zag Cat5 all over..  Oh well. 

[scharbon]

Alan is right.  If all you are doing is running 32 channels of DMX on two LE's, all you need is a DMX dongle.  If you only have an Etd, you can flash that with DMX firmwear and run it like a normal dongle directly to the first LE and daisy chain them together.

Steve

[cpnbnanamn]

It would have just been easier to set everything up if I had the right hub...   

Thanks again, guys...

[CaptainMurdoch]

It would have just been easier to set everything up if I had the right hub...   

If you want to get DMX in opposite directions with your dongle in the middle, then you could use a DMX Splitter:

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I have a v1 that I won't be using this year, shoot me a PM if you're interested.

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[tbone321]

Why wouldn't the passive hub work?  Sure, it would be sending 12V on the remaining pairs but it doesn't actually process any signals.  It simply splits the incoming signal.  While it was NOT intended for this purpose, I see no reason why it wouldn't work.  One issue with it as said before is that it will be providing 12V on the other pairs that the LE does not need or expect.  It you use a cable that is not configured properly such as a cross over cable, you could damage the LE.  If you really feel the need to use the hub as a splitter, I would remove the fuses from the ports being connected to the LE's.  Now if you have the 4 port passive hub, that should work as is but you may have some possible signal reflection issues.

[CaptainMurdoch]

Why wouldn't the passive hub work?

That would probably work as you explained, but before I started removing fuses off a hub, I'd rather just make a custom cable to accomplish the task rather than dealing with the hub at all.

Without wireless, there is now way to get around running at least one cable to each of the 3 devices (2x LE, 1x Dongle).  Using normal cabling, unless you have a splitter of some sort, you are going to need at least one LE with two cables, an IN and an OUT.  If it is too hard or undesirable to run two cables to one LE or to connect the LE's together via a direct cable, you can always feed the OUT data back onto an unused pair of the IN cable and break it out elsewhere to go to the second LE.

I'd run a cable from the dongle to the first LE passing by a location central to the 3 devices.  Then run a cable from the second LE back to that same central location.  On the dongle end, wire the RJ45 as normal.  In the first LE, break out the brown pair and terminate it on positions 1 (white/brown) and 2 (brown) of a RJ45 connector.  Connect the orange pair as normal on another RJ45 connector.  Connect the orange RJ45 to the DMX IN on the LE. Connect the brown RJ45 to the DMX OUT.  Go back to the central location where the cables meet.  Split open the jacket on the cable that passes through and cut the brown pair.  Solder the brown pair from the end that goes to the first LE to the brown pair on the other cable that goes to the second LE.  At the second LE, crimp another RJ45 on the brown pair using the same pinout as the brown pair at the first LE.  Connect this RJ45 to the DMX IN.  Remove terminator in first LE and terminate on the second LE.

This daisy chains the LE's together but there is only one cable going out to each device.  This only costs the Cat-5 and 4 RJ45 connectors and doesn't require power or any device other than the dongle and two LE's.  This only works in the case of the two LE's, you couldn't connect up another LE using the brown pair, but you could use the same logic to go out to another LE using the blue or green pair and only have one Cat-5 out to the LE's from the central location.

[n1ist]

For a quick test, grab an RJ45 splitter from the dollar store and plug it directly into the dongle.  The stub should be short enough that it will be OK.
/mike

[tbone321]

It sounds like he is just trying to reduce cable runs.  His LE's are probably on opposit ends of the yard and his dongle is in the middle.  He just wants to split the signal and send a single line to each LE.  Removing the two fuses is just a safety measure to prevent 12V from being sent to the LE's and to me, is much easier than creating custom cables that can later be mixed up with the normal ones and cause other issues. 

[chrisatpsu]

i thought splitting the cable might introduce issues with the signals going in two directions.  without getting too technical, the term ringing comes to mind.

[CaptainMurdoch]

If crosstalk were an issue then we wouldn't be able to use the ether dongle which uses all four pairs for different universes.  It is also a differential signal as well which helps.

Regarding mixing up the custom cable with others.  It would be pretty hard to mistake a 3-way 4-RJ45 cable with two connectors in one of the legs with a normal cat-5 with only one connector at each end.  If you are talking about mixing up one end, the only normal end is in the dongle side and you'd have the same potential to mixup that as you would any other cable.

That being said, I'd test with a stubby RJ45 splitter as mentioned and see if that works if all cables can come back to the dongle.  I don't think the dongle has a terminating resistor so that should work to have it in the middle.