# Multiple DMX universes over single CAT5?



## FatherMurphy (Feb 5, 2013)

The guys in the install section of the company I work for have hit across an odd one - we need to send four to six runs of DMX to the ceiling of a church with a high, steep gluelam beam roof. There is no access through the roof itself, so all wiring will have to be surface mounted, and the roof is inaccessible enough that we don't want anything other than the fixtures themselves up there, so no splitters/wireless receivers, just hard wires from the control to the fixtures.

One solution that has been asked about is running more than one universe down a CAT5 line, thus keeping the exposed and visible wiring to a minimum. The guys at Fleenor suggest that this is possible, but they didn't want to get into specifics, basically claiming that they make boxes to go on the ends of cables, not cabling itself (Knowing how much variation can occur in the precises specifics between cable types and between manufacturers, I don't blame them).

My understanding of DMX over CAT5 is that you typically use one pair (most often orange) for signal +/-, and both wires together of another pair (often brown) as shield.

So, has anyone tried using two or three pairs as +/- for additional universes? Any specific cable specs to seek or avoid? Potential shielding difficulties breaking the universes apart as the different groups of fixtures are approached?

Thanks in advance.


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## sk8rsdad (Feb 5, 2013)

If you were to put DMX gateways on either end of the CAT5 then you could convert DMX to Artnet, eDMX, or sACN and then convert back to DMX on the far end. The most ports I have seen on a single gateway is 4 so it would take multiple gateways and an ethernet switch in the ceiling to get to 6 ports. I'm puzzled at a church needing 6 universes of DMX though. What is triggering the requirement for 6 separate DMX runs? Maybe part of the solution is fewer runs and and a opto-splitter.


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## MNicolai (Feb 5, 2013)

TMB makes a product for that: http://pub.tmb.com/SneakSnake/pdf/SneakSnake-LTR-web.pdf

The trick is that for 4 universes on the same CAT5E cable, you have to use STP cable instead of UTP. UTP is fine for 2- or 3-universe flavors, but to get 4 universes on the same cable, you need an extra conductor to use as the ground, which TMB uses the shield on an STP cable for.

sk8rsdad presents another option of using networkable nodes, but that'll be far more expensive than a break-out cable and a break-in cable for the CAT5E STP cable. I share in his curiosity though as to why they need that many DMX universes at the same location.


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## JD (Feb 5, 2013)

MNicolai said:


> TMB makes a product for that: http://pub.tmb.com/SneakSnake/pdf/SneakSnake-LTR-web.pdf
> 
> The trick is that for 4 universes on the same CAT5E cable, you have to use STP cable instead of UTP. UTP is fine for 2- or 3-universe flavors, but to get 4 universes on the same cable, you need an extra conductor to use as the ground, which TMB uses the shield on an STP cable for.
> 
> sk8rsdad presents another option of using networkable nodes, but that'll be far more expensive than a break-out cable and a break-in cable for the CAT5E STP cable. I share in his curiosity though as to why they need that many DMX universes at the same location.



One thing about the roof on a church, it's usually wood. The line is going to make a nice receiver for EMP from nearby lightning strikes. There is a similar run (Ethernet not dmx) at a church I deal with (slab construction) and I have to replace hubs on a regular basis in the summer/storm season. Just something to keep in mind.


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## SteveB (Feb 5, 2013)

"I share in his curiosity though as to why they need that many DMX universes at the same location."

Yup. 6 universes is easily 96 fixtures @ 32 addresses per fixture (16 fixtures per universe).

Is there something you are not telling us as to the need for that many ?. This just doesn't seem like a system that has that much gear in a wood ceilinged church, unless it's all Selador 7 color LED's and LOT of them !

Anyone know if Belden makes a DMX compliant cable that has 6 sets of twisted pair ?. That would be my choice.


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## techieman33 (Feb 5, 2013)

The way I read it they need 6 runs, not 6 universes. They just want one cable so it's low profile, and not to have any splitters in the air since it's hard to get access to anything in the ceiling.


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## xander (Feb 5, 2013)

techieman33 said:


> The way I read it they need 6 runs, not 6 universes. They just want one cable so it's low profile, and not to have any splitters in the air since it's hard to get access to anything in the ceiling.


6 runs to the same place would mean 6 universes. Or you're doing it wrong...No?


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## epimetheus (Feb 5, 2013)

Belden 9844 would get you 4 DMX (RS485) compliant pairs with a 0.39" OD. Two of these would be fairly low profile.


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## techieman33 (Feb 5, 2013)

xander said:


> 6 runs to the same place would mean 6 universes. Or you're doing it wrong...No?



Not necessarily. You could have 6 runs coming off of an opto run together to the ceiling until they need to split off to reach separate pipes. It sounds like they want a clean looking install so it would make sense to not want cable backtracking all over the place to get to all of the pipes.


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## cbrandt (Feb 6, 2013)

It is more cable than running 3 or 4 universes on ethernet cable, but you can run two universes on a standard 5 pin dmx cable. I keep splitters for that in my workbox in case I end up with a bad run somewhere.


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## FatherMurphy (Feb 6, 2013)

Techieman33 has the right reading - I'm not interested in six universes as in six sets of 512 channels, but as six different runs, eliminating splitters in the air. The church in question is replacing all the house lights with LEDs, and it's a largish sanctuary, so the simple number of fixtures requires three separate runs just to satisfy the 32 fixture-per-run limit, regardless of channel count. The additional runs are for aesthetics and simplicity of wiring, given the way the fixtures are laid out and clustered.

The UTP/STP difference was exactly what I was hoping to find out, and we'll take lightning into a bit deeper consideration.


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## VCTMike (Feb 6, 2013)

Belden 9839 is six pair


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## derekleffew (Feb 6, 2013)

VCTMike said:


> Belden 9839.pdf is six pair


It also comes only in Chrome (gray), and costs >$3/foot.


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## JD (Feb 6, 2013)

Belden 9839 looks like telephone color coding. Look around your area for an MRC (Materials Reclamation Center.) Verizon and other phone companies have them all over the place, but often not advertized. Those places are gold mines for cable. Once picked up 25 pair Cat5 (yes, not 3) 250 foot roll for $10. The places are usually a warehouse that is a bit disorganized, but I've run across everything there from broadcast video cameras to expensive test equipment. Wouldn't be shocked if one had a big roll of it! Don't bother trying to call, no one ever knows anything. You just have to look around and say, "How much for that?" 

These places are the last weigh station before the smelting pot.


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