NOT at all what I'm saying. As Grog pointed out even
Martin and High End now cheat and use 3 pin connectors at times.
Whether it's a 3 pin
XLR connector or 5 pin
XLR connector doesn't matter. What matters is the type of cable. A 3 pin
XLR connector technically does not meet
DMX 512 standard, but there's nothing wrong with it as long as it has the proper cable attached. The DMX-512 standard requires 5 pins. But we only use 3 pins. Pins 4 and 5 were reserved for feadback features that have only been used once or twice in the 20+ years that
DMX has been around. The low end manufacturers like AMDJ, Chauvet, and Elation said, "Many of our customers are DJ's. Their gear is typically located on
stage very close to where they are operating from. If we
switch to 3 pin plugs our customers can use cheap mic cables. At that short of a distance, and only running a few fixtures, you really don't need
DMX standard cables". Over time it's become more acceptable and now even the big boys put 3 pin
XLR connections on their fixtures (The $10,000+
Martin MAC2000
Wash for example has both 3 pin AND 5 pin connectors).
Totally agreed with
Gaff on the 3 verses 5 issue. Do not ever do a Y type splitter for
DMX as it will without doubt create a loop.
A favorite saying around here:
"I run
DMX over audio cables all the time and it works."
"Well you can run
DMX signal over a barbed
wire fence, but it's not advisable."
You can
send DMX thru a shop light trouble light type spooler - very rebust signal but overall its a question of the overall length of the cable in use and its imutence - needs to be at least 110 Ohms in range but best at 120 Ohms digital grade cable that's
DMX computer language rated.
Normally such cable is available in either one pair with
shield or two pair compliant
DMX grade in the only difference being the amount of paired conductors. Overall concept in looking at such three pin cable is a
level of quality. Look at the drain/
shield wire. If not tinned (silver) it ain't of a digital grade. If even tinned but twisted instead of breaided it ain't within even reasonable standards of digital grade. For a very short run, sure it will probably work given no say
power cables near it and good connections but even for single pair cable - that which has +/- data signal and an indexed drain, you will never find a digital grade cable that is not braided and silver tinned
wire unless it is drain
wire with plastic foil
shield around the +/- conductors at best instead. Such cable with metallic foil shiled is normally about the same grade as that with a braided tinned
shield about the inner pair or two pair of conductors if four
conductor shielded.
Often
DMX cable will have both a foil
shield with drain
wire and a braided tinned
shield wire about it - good stuff and it don't matter how many pair under the
jacket. That's quality and much easier to make given the drain
wire is all you need to attach instead of trying to get a braided shiled into a
terminal. On the other
hand at times with such a plastic foil
shield, especially with multi-multi pair data cable up to 37 pair or more, that the foil just falls apart once un-bound and you have to spend extra time in just insulating drain wires. This given if index/drain/
ground/
shield the no matter which pair could potentially touch in terminating and just providing the "0" reference
point.
Anywy back to concepts, there is a lot of single pair
DMX grade cable on the market - ask your supplier for it specifically in that the only difference will be one pair instead of two pair.
Also a side note of grade of cable recently done. Instead of black & white (white goes to pin two, black goes to pin three), most digital and
DMX grade cable these days is using blue and white conductors. White still goes to pin 2. Blue and white conductors is also a sign that this cable is digital grade of a good impediance.
Never but never use two pair cable with a XLR-3Pin Plugs or you will get Gremlens in your
system. Don't matter if the manufacturer is supplying a two pair cable but of only two colors white/blue and connecting two wires per
terminal or providing a two pair cable white/blue/green/red
etc. Avoid them if possible even if the best on the market (my opinion in advise).
Want this cable to work or fail properly as single
conductor and never want a cable that tests fine dependant on how you hold it or shake it, but in a show going up situation might just have a say blue
conductor of dual blue conductors that came undone. This
in one testing situation in dual wires feeding the
outlet might just test fine but plugged into the
fixture not work properly in "gremlens in your
system." All it takes is if two wires soldered to break and one
connector to be not connected and it at the moment in being a duplicate data
line be connected in testing, but that second
wire now free floating now touching another
terminal be it drain or white. Definate troubleshooting problems within a
system should you have a free floater no matter what the color.
That said you also never want a true
DMX cable wired for three pin in conductors cut back at best or not connected to something. Such not connected conductors even if cut back still tend to travel within the cable and cause pandimonium in your
system for troubleshooting. A not connected
conductor within a cable or pair of them will do its best to travel within a cable so as to short in time in some way by way of the Gremlen in the
system concept. Just avoid such cables. Unconnected wires travel within a
jacket and cause problems often hard to detect the cause of.
Cat.5 cables in much an above similar way won't persay if cut conductors connected to RJ-45 plugs but could potentially if to XLT over time. This in addition to the solid verses stranded issue in solid
wire flexed/moved won't last as long. Sure for Cat5E cable it's about the twisting of the
wire that by way of it shields it from electrical shielding issues and often cheaper, unless stranded and more difficult to terminate, Cat.5 cable often if in constant use is not an option for doing
DMX. Some good
stage rated Cat.5 cable out there that is is a
bit more difficult to terminate but still have to worry if
portable about the not used conductors say touching something they should not with time if used and moved about.
Overall, as a single pair cable it if better grade it will probably have a drain
wire outside of a foil shileld and blue and white conductors. That's good stuff and norm these days in that I don't think I have seen a single pair cable with drain, foil
shield and tinned braided
shield wire yet. TMB might have such a thing perhaps. (Not so fair with them last time with
Soco plugs also in citing them now as best of two grades debatably between lots of other more standard
DMX cable on the market - single pair or dual pair.) ProCable from TMB is the best on the market no question even if that dual
wire pairs for the
XLR and outer
jacket melts easily. Their other grade also is at least standard for the industry normal.
Overall concept, want the ProCable to last forever, don't let it touch a hot light or nobody installing it will use it once melted down even if "it still works though." This however with the true
DMX ProCable in that the "single pair" cable from them has dual conductors which as above has been shown to cause problems if dual
wire. Worst ever for me was a brand not Electronic Theater Controls but with blue markings and "
ETC" on it that was dual pair and they wired the good quality cable for us as per single pair. Unfortunately they just kind of left the second pair of
wire within the
plug kind of at cut length just flopping about within the
plug... Hmm, extra full length second pair of conductors just kind of flopping about within a
plug, that's a good idea. Years later in bulk buy such cables still show up in the repair pile when found, not having been fixed or once fixed in being cut back a problem again unless made into true five pin.
Worse than that above "Gremlen in the
system" was a huge bulk buy with a very short time
line for the cable needed for a show. Their own cable, their own empoyees making the cable "We can do this" on a short deadline, they had secretarys soldering cable. Endless bulk order on a short timeline that got made with constant Gremlens that still come up years later. Short timeline to get it done, "we can do this" and a tale of years of finding the flaws.
Iron too hot and melting stuff, drain
wire not insulated
etc. Done deal.
Inspect your cable on delivery. Also a question on buying in use of 22ga, 20ga or 24ga
wire for use as best.