The 5 pin DMX Cable Religion

[Ynot]

Forgive me, but is this FAQ not just a schedule of opinions?

I don't have time to delve into it just now, but will take a look later,

Well, have had the time to scan the USITT site a little now, and OK - it would appear that yes, all things point to them stating categorically that they want the official connecter to be a 5-pin.

 

But hang on... There's a bit on this page, bout half way down, that states:

It is important to note that while we have all been using DMX512 since 1986, it is not formally recognized in the "official" standards world. A proposal to make DMX512 an International Standard was submitted to the IEC in the spring of 1999. In August, the application was approved by IEC Technical Committee 34 and the proposed standard was designated "Entertainment Technology - USITT DMX512-A (IEC 62136)."

This suggests to me that until 1999, there was no actual internationally recognised standard for DMX....

So at that point there was nothing to compel manufacturers to fit their kit with any specific connector.

And even since the 1999 agreement, what has there been that makes it mandatory for them to use 5-pins? Regardless of the status of the USITT, there's certainly no legal onus on Martin or whoever to provide 5-pin and JUST 5-pin.... is there?

Is there a legal statute that would allow USITT to take action against any company who designs a fixture that operates from DMX, sticking a 3-pin or whatever on it and labelling it as DMX?

 

Again, don't get me wrong - I'm just playing devil's wotsit here - but I do think it's a little naive for anyone to expect a standard to be adhered to after the fact of it's formalisation by all concerned.

 

And again, I'll show the cost card... Cost is a big issue with the lower end of the market. Your average DJ is going to WANT his kit to have 3-pin sockets, because that means he CAN use his cover-all mic leads he gets cheap from Maplins, and not have to keep two different sorts of XLR cable. That means he has to buy less connectivity. And it's just that niche of the market (which overall I suspect is very BIG niche whenyou consider the number of DJs & clubs there are out there) which is most likely to have driven the reluctance of many manufacturers to use the standards.

 

OK, Martin, as I've pointed out, have started to fit BOTH 5 and 3 pins to some of their newer theatre stuff, there's still a lot of them that they advertise as just having 3-pin. Certainly all 4 of the DJ scale mirrors have just a 3-pin, yet the manuals state control is via DMX 512 (1990). Let's not forget that on that side of the user community you're likely to have fixed club installs that use the same gear time in, time out, for possibly years at a time. And the regular mobile DJ is going to use the same setup again and again. So if either place hasa DMX conversion issue, it's sorted once and that's it. We in theatre, on the other hand, are likely to see a variety of fixtures come through a varied programme and are thus going to get pi**ed off easier and quicker with whatever conversions are required.

 

This just demonstrates that whilst the USITT can make all the statements it likes about standards, it is effectively powerless to make anyone, large or small, adhere to the standards. And yes - the only way perhaps to change that is to bring customer pressure to bear.... But when companies like Martin have LOTS of DJ customers using LOTS and LOTS of their equipment and wanting to run it with 3-pin XLRs, are they likely to listen too hard to a comparitively small number of theatre users who want to press for just a 5-pin standard??

 

Sadly, I know who I'd listen to in their position!

 

I am, and always will be, a realist. Sure, I'll moan to myself the next time I have a variety of DMX movers and I need to faff around getting the pins and polarities sorted. The last time I did a big show, I had 4 Mac 250 Entours (5 and 3 pin) 4 CP Pin scans on 5 pin, 4 others on 5-pin, a CP Silverado on 5 pin, 4 LED Pars on 3 pin, a smoke machine on 5 pin, and a hazer (both, but 5-pin has broken pin 2, so used 3-pin!).

Yes, it was a pain, but one I was expecting to be, and I knew I needed to approach the wiring logically to make sure I got the orientation right all through.

 

So, as I said before - much as I'd like to get the standard to be, well, standard, I know that it won't - not in my working lifetime anyway, so why fret so much about it? Simply saying over & over that "5-pin is THE standard and it can't be called DMX if it's not 5-pin" is going to get no-one anywhere.

 

Personally, I'd rather worry about the REAL issue of DMX problems, and that's using the right cable and correctly termination the runs. THAT sort of thing is what can affect the operation of the kit, NOT whether it has 2 few pins on the socket!

[dbuckley]

Rising to your Devils Advocacy...

 

DMX512 is and always has been a standard, the first two revisions being under the auspicies of the USITT, but the USITT is not a formal standards making body, which is a different thing altogether.

 

The third revision is under the auspicies of a standards making body, so DMX512-A has an "official" classification and status.

 

Now that DMX512-A is a "proper" standard it could be adopted into national law of countries, something that would not have been possible under the first two revisions. If it were adopted as a national law, then that would be interesting, as it would mean that nations could prosecute purveyours of non-compliant equipment, just as they can prosecute purveyors of cars that dont meet legal standards. Not that it is likely to happen of course...

 

Certainly all 4 of the DJ scale mirrors have just a 3-pin, yet the manuals state control is via DMX 512 (1990)

 

And there you have it, thats a lie. You cant be conformant to the 1990 spec and have XLR-3 connectors.

 

But can anyone do anything about this disgraceful business practice? Only if someone were to go to the trading standards people and lodge a complaint. But that wouldn't work as you dont buy these things as a consumer. No, theres nothing to be done.

 

It's like the good old days in the UK when we had 2A, 5A 13A and 15A sockets all in one house, how much simpler it is when we have just one type...

[SeanT]

ESTA has carried out research and have found CAT5e cable perfectly capable of carrying DMX data.

 

We've had a CAT5e infrastucture installed which coped admirably with DMX and ethernet data.

 

 

Did they do their research with STP cable or UTP?

[pritch]

ESTA has carried out research and have found CAT5e cable perfectly capable of carrying DMX data.

Did they do their research with STP cable or UTP?

 

I believe they used both (I was having a read of the paper earlier, but I can't be bothered going to find the URL to post it here, sorry!).

 

What they didn't mention is the environment that the cable was in, whether it was affected by nearby power cables and whatnot like it would be in the real world. Yes, I know it should be separated, but at some point it has to come near to the power.

 

I'm in a bit of a quandry about it myself as to whether I should use Cat5 or spend more money and go for Belden 9829 or something for our new install.

[dbuckley]

From memory STP is recommended for installs, or UTP in metal conduit.

 

Interference from power is most unlikely to be an issue.

[thinkoutside]

I think some of you have really missed the point. At the end of the day, the only real thing that matters is that were able send our lights a set of commands that we are reasonably assured they will follow with level of reliability that match the price for which we paid to send those commands. Some sub categories of that concept are that the cable be durable, flexible (easy to work with/store), and able to distinguish from other cables. ANY MEANS of reaching that goal are all that matter to me.

 

The standardization of some of these connections sometimes serves that goal and sometimes it does not. When it doesn’t, I feel no qualms about using a nonstandardized form of data transmittion to meet my goals. Standards are there to serve the user not for the user to server them. If 2 cables can perform with the same reliability but one of them is standardized and is more expensive then it makes no logical sense to buy that one just because it has that distinction.

 

Many other people as well as I have Martin lights that can only be connected with 3 pin cables. There are 3 pin cables that have the same quality of signal transfer as 5 pin DMX cables and my goal was to see which of those cables would be values while still not give up any reliability. Using a 5-pin cable was not an option whether I wanted to or not.

 

I labeled this discussion the “DMX Religion” and I think I was dead on. It seems as if some here are on a DMX Standardization crusade but they have forgotten that it’s not about what some committee tells the consumer they can or can not do but it’s about what works best in the real world. BTW: thanks Ynot for alluding to this concept as well.

 

Along with other things I find the current standard is just too expensive per foot. Like any other industry, it’s only a matter of time before buyers get sick of working with dated technology, manufactures see that that demand, create something better, and a new standard if formed. Repent from your false god protocol and come back to reality. :) Were all just trying to make the most logical choices about wiring lights. :(

 

OK, I know it’s coming but just for kicks, why don’t you start the rebuttal with “Back in my day…” and end it with “Because I said so.” :)

[dbuckley]

I think some of you have really missed the point.

Nah. You're so far wide of the mark it's untrue.

 

Heres the equation:

 

Time available for programming = time in venue - time take to get the effing rig to go.

 

For example, most Martin movers are three pin, some are both. Some Highend movers are five pin only, some are both. My DMX512 distro has both three pin and five pin presentations. Can I take a collection of mic cables with three pin XLRs and daisychain together Martin and Highend fixtures from my splitter and have it all work?

 

The (honest) answer is I dont know. But what I do know is that if I use the five pin cables it will work. But based on experience, my guess is that 3 pins will probably need pin 2-3 swappers somewhere.

 

So by using five pin cables I get more programming time (so a better show) or more sleeping time (so a less tired person, probably making for a better show), both of which are far more important to me than the cost of a few cables, which compared to the sunk cost of kit I have plus what hire costs will be for the really expensive stuff I hire, the difference is trivial.

 

Of course, you may rate your programming time, your sleeping time, or quality of show differently than I do, which is entirely your right.

 

So at the end of the day, using the right connectors (and other stuff) isn't a religion, it's pathway to slackness to save me time, which is usually the thing that has most constraints associated with it. I can bend some constraints (eg insufficient power, insufficient kit) with money (hire a genny or other kit), I cant change the laws of physics (lights do not go through walls), and I cant get time back once its gone.

 

On a slightly related note, its not just DMX512 connector madness those of us in New Zealand face; for conventionals we use 12 channel dimmers that run off three phase 30(ish) amps, but, we have two standards for 32A connectors, the PDL 56 series and C17 32A red. Most venues are the former, some (mostly schools or establishments allied to schools) are the latter. It is indeed a t*at when your rig has one and the venue has the other......

[Pete]

I think DMX religion is probably not such a good name.

This point has been discussed before and the decision that was generally reached was that by using sub standard cable etc you were endangering your control line. Fine if you a NJD boy and your scans behaving strangely isn't a problem.

 

You say that the correct stuff is to expensive per foot. I cant see how this is true. I wouldn't like to be on your crew the day the cable lets you down,because it will be on a key job for your biggest client.

 

I'd also like to say that provoking people with lines such as "OK, I know it’s coming but just for kicks, why don’t you start the rebuttal with “Back in my day…” and end it with “Because I said so.” Probably isn't in the best spirit of the board.

[Ynot]

I think some of you have really missed the point.

Nah. You're so far wide of the mark it's untrue.

 

Heres the equation:

 

Time available for programming = time in venue - time take to get the effing rig to go.

I have to agree with ThinkOutside...

I also agree with your equation.

But the point is that unless you go out of your way to spec equipment that ONLY has 5-pin connectors (pretty difficult these days!) then you WILL come across the scenario of mixed cabling. And quite often, you will have no control over what fixtures you have to use, unless you spec everything that you ever work with and never work someone else's design.

For example, most Martin movers are three pin, some are both. Some Highend movers are five pin only, some are both. My DMX512 distro has both three pin and five pin presentations. Can I take a collection of mic cables with three pin XLRs and daisychain together Martin and Highend fixtures from my splitter and have it all work?

 

The (honest) answer is I dont know. But what I do know is that if I use the five pin cables it will work. But based on experience, my guess is that 3 pins will probably need pin 2-3 swappers somewhere.

 

So by using five pin cables I get more programming time (so a better show) or more sleeping time (so a less tired person, probably making for a better show), both of which are far more important to me than the cost of a few cables, which compared to the sunk cost of kit I have plus what hire costs will be for the really expensive stuff I hire, the difference is trivial.

I think that MOST people here, (definitely including me) will advocate the use of correct cable type, regardless of the connector format. BUT if you have a string of, for example, 6 older Macs, with only 3-pin outs/ins, are you saying that you would run 5-pin cables twixt them all and convert them all 5 to 3 at each end...? I somehow doubt it. It is forthis reason that at my venue we have a growing stock of both 3 and 5 pin cables (using the correct cable), and a growing set of adapters and converters. That way, when I run those 6 Macs, I have just ONE converter to worry about on that string (at the start) to convert from the 5 pin out of the desk, and the rest just fall into place. If we take your stance literally, then it would be time-wasteful to do it your way.

 

An old adage springs to mind, here, whilst considering all that's been written on this topic...

Something like...

Oh, Lord, grant me the wisdom to change what I can, but accept that which I cannot

 

Somehow seems appropriate here!

 

TD

[dbuckley]

BUT if you have a string of, for example, 6 older Macs, with only 3-pin outs/ins, are you saying that you would run 5-pin cables twixt them all and convert them all 5 to 3 at each end...?

No, same as you, chain 'em all together. But that wasn't the point of my point. My point was that with two different manufacturers fixtures both with 3 pin XLRs, what do you do... Do you (a) chain them all together and hope it'll work, or (b) chain them in two chains both back to the distro so you only have one place you need to insert a swapper? See, thought is required, and if the rigging is being done with someone who doesnt appreciate the finer points of the potential problem, it could be plugged up before you've noticed, so it may all need to be done again. This is all because XLR3 is not a standard, so there is no right or wrong way for pins 2&3 to be wired, and so different manufacturers .do it one way or the other.

 

If the fixtures were all five pinners, you woudn't need to give it a second thought - just plug them all together and it'll work. Thats because XLR5 is standard,

 

And lets not forget that ythe OPs central point is about cost of cable, rather than number of pins.

 

Oh, Lord, grant me the wisdom to change what I can, but accept that which I cannot

Oh yeah, in spades. And now that there are alternatives to Martin in my local hire marketplace, I can vote with my wallet! Perhaps the unchangeable can change, at least from one person's perspective...

[Pete]

I think that MOST people here, (definitely including me) will advocate the use of correct cable type, regardless of the connector format. BUT if you have a string of, for example, 6 older Macs, with only 3-pin outs/ins, are you saying that you would run 5-pin cables twixt them all and convert them all 5 to 3 at each end...? I somehow doubt it. It is forthis reason that at my venue we have a growing stock of both 3 and 5 pin cables (using the correct cable), and a growing set of adapters and converters. That way, when I run those 6 Macs, I have just ONE converter to worry about on that string (at the start) to convert from the 5 pin out of the desk, and the rest just fall into place. If we take your stance literally, then it would be time-wasteful to do it your way.

 

I know of a major rock n rose tour that's out at the moment. Most of the fixture are high end studio buckets.The others are a mix of MAC 2Ks and VL2416s. The colors are much in abundance,but its those that are turned around to 5 pin not the other way round.

[Leggy]

as long as the cable is the right quality, there is no reason not to use 3 pin. afaik, all fixtures have pins 2 and 3 wired the same these days, the times of using a pin swapper on martin fixtures ended quite a while ago (unless you are using very old units!)

3 pin connectors have a massive advantage when on tour in that the pins are far harder for local crew to bend when trying to plug them in, I've seen many a 5 pin XLR trashed by someone not understanding or paying attention to what they were doing. many major tours use 3 pin for this reason.

 

Leggy.

[Pete]

many major tours use 3 pin for this reason.

 

Erm,possibly,but all the ones Ive ever done work for were 5 pin

[jayselway]

Just to throw a spanner in the works (braced for impact here!!!)....

 

I have a small lighting desk, which I take on regular gigs with a particular band. It's a Q12 with some features on it, but I mainly use 2 banks of 12 presets and the chase memory in it. It doesn't have to do much work, as for those gigs I take the larger Jands.

 

Now... my dimmers are on 5-pin XLR DMX input, or 37 pin Control Socapex split out between the two Betapacks. However, my desk, is on 5-pin DIN - "DMX Specification correct to 1990" - as labelled on the back. If only it was on XLR-3 or 5!!!!

[Leggy]

many major tours use 3 pin for this reason.

 

Erm,possibly,but all the ones Ive ever done work for were 5 pin

 

 

actually, erm, definitely......