# DMX/Cat5



## Catwalker (May 21, 2015)

I have an event coming up that requires more 5-pin DMX cable than we either have, or could conveniently acquire. I am curious, would it be possible for me to get 5-pin DMX ends, then put them onto Cat5 cable? Would such a connection be reliable?


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## MNicolai (May 21, 2015)

DMX cable is pretty cheap to rent. Find a rental house and get a quote. Depending on how long you need it for, there's a fair chance it'll be cheaper (and much more reliable) than you building cables yourself.


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## techieman33 (May 21, 2015)

I agree with MNicolai rent the cable, using Cat5 just isn't worth the risk.


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## JD (May 21, 2015)

Cat 5 works fine for DMX conduit runs but not for general stage use. It is unshielded (a problem to some degree when not in conduit) and generally is pretty fragile. Depending on your skill sets, I have never had any problems soldering it to 5 pin XLR connectors for wall plates (Although there is a punch-down version by ETC that is far preferred.) But, again the question that comes to mind, Why go to all the trouble to make a mess of unreliable cables when you can just rent them for this application?
One other problem, in-line connectors generally use a compression strain relief which is capable of squish-shorting the pairs in Cat 5.


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## Les (May 21, 2015)

I had a "fun" experience trying to rent DMX cable here in Dallas last month. Called *Gemini Stage Lighting* - nope, they won't rent me cable. They don't want to run out when doing productions. PSAV? No dice. Some other company which I forgot the name of -- sure, but you have to endure a lengthy application process in order to become our customer.

All I needed were a few 50's and a couple 25's. I ended up going to Barbizon and buying the $%^& cable...


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## petercav17 (May 22, 2015)

I have successfully made a couple long ethernet cables into DMX because it was so cheap. But they're fragile and therefore I'm forced to be very careful. I'm the only one who uses them and I only put them on long or semi-permanent runs where no one will touch them. Last month we had a DMX shortage and I had to use one on stage in a pinch. I had another gig to go to and the kid that struck the cable coiled it poorly and created a crack down the side, and almost ripped a connector off. Beware!


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## JD (May 22, 2015)

I will confess, I have done it before. At least 3 times. In each case it was a matter of a long cable run that was so labor intensive to put up that it was not worth tearing it down. One was a venue owner who demanded the cable be routed above about 100 feet of suspended ceiling. I told him if he wanted it that way he would have to do it himself and he agreed to. So, I gave him a roll of Cat 5 and the day of the gig I soldered on the ends. At teardown, I cut the ends off and left it there. (He must have zip tied it somewhere because it wouldn't pull out.) Worked fine, but I did have a surface backup plan if there was trouble.
One of the real dangers of Cat 5 is that the insulation is designed to be displaced on a punchdown block. Because of this, it can easily get pushed out of place and short. I had that happen on one of these jobs when using the older switchcraft connectors that use the two compression set screws. The cable was dead, so I pealed back the ends and found the conductors had lost their insulation right at the strain relief gland. Simple answer is don't crank down on the strain relief. After all, it's only getting used once anyway, just make sure there is no strain!


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## RickR (May 22, 2015)

Please be aware that "Cat 5" is a speed rating for ethernet and NOT a wire type. 

Most of the above discussion seems to relate to solid core, unshielded stuff rate only for permanent installation even for ethernet. There are many cables rated for cat5 and most are also rated for RS-485 which is the basis for DMX. DMX requires shielding. Portable cables are usually stranded wire, with a tough outer jacket.


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## rphilip (May 22, 2015)

RickR said:


> Please be aware that "Cat 5" is a speed rating for ethernet and NOT a wire type.


This is exactly wrong, Cat 5, Cat5e, Cat6, Cat6A are all classes of specification for the wire. To meet a rated as a CatX cable it must meet or exceed standard for things like loss up to a specified frequency, return loss, impedance and many more. Many people associate Cat5 with 100MB/s networking as that's the fastest ethernet speed for which Cat5 meets' the standard, Cat 5e and 6 both will run Gigabit (1000MB/s), Cat6a or Cat7 is required to meet the specification for 10GB/s ethernet.

The exact construction of the wire (stranded vs solid) and what type of shielding are mostly independent of what level a cable is rated to.

Philip


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## Footer (May 22, 2015)

RickR said:


> Please be aware that "Cat 5" is a speed rating for ethernet and NOT a wire type.
> 
> Most of the above discussion seems to relate to solid core, unshielded stuff rate only for permanent installation even for ethernet. There are many cables rated for cat5 and most are also rated for RS-485 which is the basis for DMX. DMX requires shielding. Portable cables are usually stranded wire, with a tough outer jacket.



No, Cat 5 is a wire type. The Category 5 (and Cat 3, 5e, and 6, multimode fiber, singlemode fiber, and coax) standard which is built into the TIA-EIA 568 standard are all different standards that the TIA had made. On top of that, they specify which Ethernet standards can work over that type of cable. These are the 803.x standards. They say how the cable should be built and what specs it should test to. They don't care what you run over it. In fact, the Category standards are all designed to deliver POTS service first then were adapted to data. This is why your pins 4 & 5 are terminated in a single pair because POTS lines use the center pair.

And... there is a standard in the industry on how to do this. http://www.etcconnect.com/Support/Articles/DMX-Over-Cat5.aspx

There is nothing wrong with running DMX over Cat5 cable. I do it all the time. You'll be fine.


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## RickR (May 24, 2015)

Sigh. 
If you simplify something far enough it's wrong.


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## JD (May 25, 2015)

Well, it's kind of both.
I grew up in the old telco days. Most of that stuff had no use for data. The standard rating was (and is) Cat 3. When computer networks became popular, engineers were looking for something to make network installs easier and they looked to the pre-installed phone systems. Many systems were put in with 25 pair cables, but even simple systems were put in with 6 pair. (blue/orange/green/brown/gray/red-blue) It occured to them that many of these pairs were not in use. Regular telephone (POTS) is put on the blue/white pair. The thought was, how much speed could you get using dedicated twisted telephone cable? The answer was 10Mhz. Thus was born the 10BaseT Ethernet. It shared all the same equipment that the telephone system used. As time evolved, more speed was needed. By changing the physical construction of the cable and upping the number of twists, the speed could be increased 10 to 100 fold. Cat 5 is a general term that we think of for 4 pair network cable. Truth is, there is also 25 pair Cat 5. Same high twist and impedance. Again, the thought was to use this wire throughout the building for both network and telephone. However, the telephone industry was also changing at a rapid rate! New digital phones used 2 pair or even all 4 pair of the cable. Thus, installing the telephone system and installing the network parted ways. Still, as with many things, the legacy remains.


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## BillConnerFASTC (May 25, 2015)

I thought cat 5 was both a type of wire but also the wiring "standards" that go with it, which all together provide a certain capicitance and resistance range, and allow for - or assure - a certain minimum data speed. Its probably still cat 5 wire if you do a sharp right angle bend or exceed a segment length, but doesn't seem you can call it cat 5 then.

Why would you have to have a certain training and instruments to certify it as cat 5 if it was just the cable, because I could read what's printed on the jacket.

Please correct me if I'm wrong.

BTW I've been told that DMX actually works better on cat 5 cable than the typical Belden called out.


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## TheTheaterGeek (May 25, 2015)

I have had some success converting some EtherCon cable we had lying around into dmx. But isn't that basically the same kind of cable with EtherCon connectors on it instead of 5pin?

Also would some heavy duty CAT5 work for your budget?
http://store.haveinc.com/p-50143-ge...3uwvpUnZtdTXNuOHGVrrxQ7SFI3Veyv-k8aAlai8P8HAQ


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## JD (May 25, 2015)

BillConnerASTC said:


> I thought cat 5 was both a type of wire but also the wiring "standards" that go with it, which all together provide a certain capicitance and resistance range, and allow for - or assure - a certain minimum data speed. Its probably still cat 5 wire if you do a sharp right angle bend or exceed a segment length, but doesn't seem you can call it cat 5 then.
> 
> Why would you have to have a certain training and instruments to certify it as cat 5 if it was just the cable, because I could read what's printed on the jacket.
> 
> ...


Cat 5 is the "wire" standards for speed and impedance etc. The 803.x standards are for the "wiring" as in cable, connectors, etc., just as DMX is a "wiring" standard, although wire that meets those standards we call DMX cable. Cat 5 lacks a shield, but when run through conduit works probably better than standard "DMX" cable. Outside of conduit becomes a question but we have all done it  Noise rejection is the question, but I've also run ClearCom through Cat 5 and had it sound clean, so it does pretty well even in that department. Of course, DMX is an old and very slow data format, so I would suspect if a cable is good enough for 100 Mhz, it can probably handle the 250Khz DMX signal! Now, the main problem as I see it comes when using the super cheap Cat 5 that is a solid conductor. Easy to damage, easy to break. Still, for a one-shot throw away run, it has worked fine for me. There are far more durable versions of Cat 5 and Cat 6, but their price per foot is about the same as DMX, so there is no tangible advantage that comes to mind.


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## danTt (May 25, 2015)

TheTheaterGeek said:


> I have had some success converting some EtherCon cable we had lying around into dmx. But isn't that basically the same kind of cable with EtherCon connectors on it instead of 5pin?



Ethercon is ethernet cable with a locking connector. You can run dmx over it the same way you can run dmx over standard ethernet cable, but you can't run ethernet systems over standard 5 pin dmx cable. So I wouldn't say it is the same kind of cable.


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## TheTheaterGeek (May 25, 2015)

danTt said:


> Ethercon is ethernet cable with a locking connector. You can run dmx over it the same way you can run dmx over standard ethernet cable, but you can't run ethernet systems over standard 5 pin dmx cable. So I wouldn't say it is the same kind of cable.



I meant same sort of cable as in EtherCon vs Straight CAT5. I realize I didn't portray it right.


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## microstar (May 25, 2015)

There is also stranded Cat5 cable that takes bending and soldering better than solid.


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## Footer (May 26, 2015)

BillConnerASTC said:


> I thought cat 5 was both a type of wire but also the wiring "standards" that go with it, which all together provide a certain capicitance and resistance range, and allow for - or assure - a certain minimum data speed. Its probably still cat 5 wire if you do a sharp right angle bend or exceed a segment length, but doesn't seem you can call it cat 5 then.
> 
> Why would you have to have a certain training and instruments to certify it as cat 5 if it was just the cable, because I could read what's printed on the jacket.



The wiring standards are technically part of the TIA/EIA 568 standards. The "cat" cable standards are a very small part of that. All TIA/EIA does is set standards for each "cat" level as to what frequency it should perform to and how much cross talk is allowed at that level plus a bunch of other stuff. The do not specify how the cable is to be made or how many twists it has. They don't care. All they care about is how the cable tests. The IEEE 802.3 Ethernet standard then states what kind of cable you need for the huge number of different type of Ethernet topology's and speeds. This can range from ethernet over fiber, coax, and twisted pair. 

The reason I'm like this is I used to install Cat 5 cable for a living. When we left all we cared about what what the cable tested at. We did not care how fast it could deliver data speeds. Also, in my cisco class if you called it an "ethernet cable" you got an F for that day. You learned that one quick. 

You would actually be amazed what you can do to a Cat5 or Cat6 cable and still have it test out OK. Most issues actually come due to the termination, not the actual run. Keeping those twists right up to the punchdown block really makes a difference.


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## AlexDonkle (May 26, 2015)

Footer said:


> You would actually be amazed what you can do to a Cat5 or Cat6 cable and still have it test out OK. Most issues actually come due to the termination, not the actual run. Keeping those twists right up to the punchdown block really makes a difference.



How much abuse it takes also depends on whether you're dealing with bonded-pair CatX cables or not. 

As you said though, it is difficult to field terminate without reducing the frequency range of the cable. There's a lot of Cat6 cable installs that don't pass nearly the full frequency range of the cable due to this, but the slower speed is rarely noticed by most.


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## Jay Ashworth (May 26, 2015)

Microstar is the only commenter I've seen who nailed it here:

Nearly all "Cat5" rated ethernet cable is solid conductor.

You should never use solid conductor wire for "cord sets"; cables intended to be moved and stowed on a regular basis. Those should always be stranded.

You can *get* stranded Cat5, as well as 8p8c connectors (*please* don't get me started on "RJ-45" ), but it's more expensive.


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## BillConnerFASTC (May 26, 2015)

Jay Ashworth said:


> Microstar is the only commenter I've seen who nailed it here:
> 
> Nearly all "Cat5" rated ethernet cable is solid conductor.
> 
> ...




You like those over Neutrik's ethercon on Proplex cables? I like the fact that you can use a commonly available ethernet patch cord with RJ45's in a pinch, and just seems harder to come up with more cords with 8p8c connectors at the last minute. But we agree that the plain RJ45 patch cords are a poor permanent solution.


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## AlexDonkle (May 27, 2015)

BillConnerASTC said:


> You like those over Neutrik's ethercon on Proplex cables? I like the fact that you can use a commonly available ethernet patch cord with RJ45's in a pinch, and just seems harder to come up with more cords with 8p8c connectors at the last minute. But we agree that the plain RJ45 patch cords are a poor permanent solution.



Ethercon Cat6 rated connector uses 8p8c, which is what we standardize on for most of our jobs. The older ethercon Cat5e connector with RJ45 work great, but can't pass Cat6 data speeds. My guess is we'll see more and more 8p8c as Cat6 becomes common in more venues.


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## BillConnerFASTC (May 27, 2015)

AlexDonkle said:


> Ethercon Cat6 rated connector uses 8p8c, which is what we standardize on for most of our jobs. The older ethercon Cat5e connector with RJ45 work great, but can't pass Cat6 data speeds. My guess is we'll see more and more 8p8c as Cat6 becomes common in more venues.



We looked at this just recently and - for lighting - and the manufacturers we asked had no plans even to adapt this. Have you found a node from pathway or etc that will mate? I seem to recall that it would be a major change because the receptacle is larger and won't fit in the current boxes.


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## robartsd (May 27, 2015)

From what I can find, RJ45 is a wiring standard for 8p8c connectors. There are some RJ45 variants that use physically keyed variants of the 8p8c connector and there are other wiring patterns for 8p8c connectors that frequently get called RJ45 anyway because many people associate RJ45 with the connector rather than the wiring pattern of the connector. Some wiring patterns for 8p8c connectors are not compatable with high speed data because they space the contacts for a pair of wires too far apart to keep enough twist near the connector.


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## GreyWyvern (May 27, 2015)

http://en.wikipedia.org/wiki/Registered_jack


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## AlexDonkle (May 27, 2015)

BillConnerASTC said:


> We looked at this just recently and - for lighting - and the manufacturers we asked had no plans even to adapt this. Have you found a node from pathway or etc that will mate? I seem to recall that it would be a major change because the receptacle is larger and won't fit in the current boxes.


We have not run into that actually, nearly all equipment like lighting nodes and digital audio stageboxes with ethercon jacks on our jobs are permanently wired into fixed or rolling racks with security screws. Primarily due to theft concerns from the school, as it is very common across the state. We use ethercon jacks primarily for either patch panels or wall / floor plates where custom-wired lecterns or stage manager's racks plug in. This is also driven by the state procurement rules for "portable equipment" vs. "built-in equipment", but that's a whole other can of worms.


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## BillConnerFASTC (May 27, 2015)

AlexDonkle said:


> We have not run into that actually, nearly all equipment like lighting nodes and digital audio stageboxes with ethercon jacks on our jobs are permanently wired into fixed or rolling racks with security screws. Primarily due to theft concerns from the school, as it is very common across the state. We use ethercon jacks primarily for either patch panels or wall / floor plates where custom-wired lecterns or stage manager's racks plug in. This is also driven by the state procurement rules for "portable equipment" vs. "built-in equipment", but that's a whole other can of worms.



We use portable nodes quite a bit, catwalks and electrics for instance.


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## AlexDonkle (May 28, 2015)

BillConnerASTC said:


> We use portable nodes quite a bit, catwalks and electrics for instance.


Makes sense then. It looks like Neutrik's new Cat6A jacks released this year will intermate with the Cat5e Ethercon connectors though.


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## Jay Ashworth (May 29, 2015)

What Robartsd said. Unless you are an installer for a wireline telephone company working on esoteric data arrangements that nobody uses anymore, you have never touched an actual RJ-45 in your entire career. 

It is not a technically accurate name for anything else using an 8p8c modular connector. Jack or plug.

That was the point I was trying to make earlier. When I was half asleep.


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## GreyWyvern (May 29, 2015)

It seems to me that the CB wiki entries for RJ45 and 8P8C should be swapped. RJ45 should send you to 8P8C.

*Also, for whatever reason, RJ45/RJ-45 isn't auto linking in the wiki or in posts, making it not possible to simply click through. Have to search instead.

Edit: Here is the link to the wiki http://www.controlbooth.com/wiki/?title=RJ-45
Also, to be technically correct, the hyphen should not be in it. I did add it in the 8P8C entry to try to get it to link.


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