# DMX vs. DMX512



## derekleffew (Dec 31, 2010)

Recently came across this...
From Pathway Connectivity Inc. - DMX Vs DMX512... :

> Members of ESTA's Control Protocols Working Group will generally complain if you don't refer to the industry standard lighting control protocol as "DMX512" and not simply as "DMX." You might wonder why...
> 
> ...To help you remember, ESTA's Technical Standards Manager, Karl Ruling has penned this rap:
> _DMX Five Twelve is the name
> ...


Mr. Ruling _et al_ seem to have lost (or surrendered) the battle. Perhaps the new push is/should be to call it ANSI E1.11 - 2008 ? Thoughts?


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## mstaylor (Dec 31, 2010)

It's catchy.


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## xander (Dec 31, 2010)

I'm all for calling things by their true/correct name as is discussed in this thread, What's in a name?, but with DMX vs. DMX512, there just isn't anyway that it could be confusing or misleading to just call it DMX. If I were to tell an electrician to run DMX from FOH to SR, *no one* is going to think I was giving workout instructions to a late 90's rapper. Maybe that example isn't very good to begin with because I am also using DMX to refer to a cable, when, we all know what DMX512 is a protocol, not a type of cable. So, what if we were talking about protocols? If someone were to tell me that we needed to convert the data from ArtNet to DMX, I would not ask, "Do you mean DMX512 or are we sending it to Microsoft?" 

Like you implied, DMX512 is already short for ANSI E1.11 - 2008, so why can't we just shorten it a little bit more?

My $.02
-Tim


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## chausman (Dec 31, 2010)

Not to mention, how many times are you really going to be giving out instructions like "run the DMX from FOH to SR" where you don't have time to explain what you mean. If you do have a fast situation like that, you are most likely working with competent people. If you do have to explain, you are probably working with them for the first time and are not rushing to get things done. 

And...I didn't even know there was a rapper named DMX or a Microsoft group.


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## epimetheus (Dec 31, 2010)

chausman said:


> Not to mention, how many times are you really going to be giving out instructions like "run the DMX from FOH to SR" where you don't have time to explain what you mean. If you do have a fast situation like that, you are most likely working with competent people. If you do have to explain, you are probably working with them for the first time and are not rushing to get things done.
> 
> And...I didn't even know there was a rapper named DMX or a Microsoft group.


 
Man, what is going on with today's youth?!? 

DMX - Party Up (NSFW)

Classic...


Edit: On topic though, I think there's little chance on confusing DMX512 with the 90's rapper or data mining extensions. Unless, of course, you've got a comp sci major who's into 90's rap on your electrics crew. Then you're just screwed...


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## derekleffew (Dec 31, 2010)

xander said:


> ... but with DMX vs. DMX512, there just isn't anyway that it could be confusing or misleading to just call it DMX. ...


Now, I'm not too sure about that. 
I once had a minor fit when a new 3pin XLR jack on a wall plate appeared in an electrical room, near the dimmers, labeled "DMX". There was NO audio equipment in that room. Turns out it was a tie-line to the hotel's main audio rack room, and was carrying Digital Music Express (www.dmx.com), signal. The installers were supposed to run the line into my audio room. They eventually installed a new line to the proper room, but I labeled the heck out of the one in the dimmer room with P-Touch. Hopefully the label is still there.


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## chausman (Dec 31, 2010)

AKA, Elevator music!


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## xander (Dec 31, 2010)

derekleffew said:


> Now, I'm not too sure about that.
> I once had a minor fit when a new 3pin XLR jack on a wall plate appeared in an electrical room, near the dimmers, labeled "DMX". There was NO audio equipment in that room. Turns out it was a tie-line to the hotel's main audio rack room, and was carrying Digital Music Express (www.dmx.com), signal. The installers were supposed to run the line into my audio room. They eventually installed a new line to the proper room, but I labeled the heck out of the one in the dimmer room with P-Touch. Hopefully the label is still there.


 
I stand (or sit) corrected.



Stupid sound stuff taking our acronyms.


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## SteveB (Dec 31, 2010)

I think "DMX512/1990" would work. Catchy it is. Maybe add "With 5 pin XLR" just to be safe.


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## Tex (Dec 31, 2010)

To add to the confusion, Reebok has shoes that use DMX technology!
http://corporate.reebok.com/en/about_reebok/faq_section/technology/default.asp#What is DMX Foam?


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## DuckJordan (Dec 31, 2010)

I know this kinda clouds the waters but why is DMX short for ANSI E1.11 - 2008 what do the letters DMX stand for?


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## Les (Dec 31, 2010)

DuckJordan said:


> I know this kinda clouds the waters but why is DMX short for ANSI E1.11 - 2008 what do the letters DMX stand for?


 
*D*igital *M*ultiple*X*

A few years ago, we were trying to figure out what XLR stood for. Who was it that said "e*X*cellent *L*istening *R*eceptacle"??? 


derekleffew said:


> Turns out it was a tie-line to the hotel's main audio rack room, and was carrying Digital Music Express (www.dmx.com), signal.



Sounds a lot like a Muzak system (the OTHER elevator music providers). (www.muzak.com).


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## shiben (Jan 1, 2011)

Les said:


> A few years ago, we were trying to figure out what XLR stood for. Who was it that said "e*X*cellent *L*istening *R*eceptacle"???


 Wikipedia touches on this. Apparently it was a designation (sort of like you can get a Suburban XLT or whatever) from the original MFG. 

XLR connector - Wikipedia, the free encyclopedia


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## chausman (Jan 1, 2011)

shiben said:


> Wikipedia touches on this. Apparently it was a designation (sort of like you can get a Suburban XLT or whatever) from the original MFG.
> 
> XLR connector - Wikipedia, the free encyclopedia


 
Just remember that anyone can edit wikipedia. Not that this is any different for CB since anyone can post on it, but whit so many people who work professionally with this stuff everyday, that is is much less likely that EVERY body will be wrong and have the same wrong answer.

Oh, and It took me a while to find where it actually said what XLR stood for but it says it stands for Cannon X series, with L and Rubber.


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## Tex (Jan 2, 2011)

chausman said:


> Just remember that anyone can edit wikipedia.


 True, but when undocumented, most posts contain the qualifier "Citation Needed". The Wikipedia post about XLR connectors has a citation. 
Pro Audio Reference C
The CB wiki also has a reference.
http://www.controlbooth.com/wiki/XLR


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## chausman (Jan 2, 2011)

Just thought I would mention it.


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## blackisthenewblack (Jan 3, 2011)

Tex said:


> To add to the confusion, Reebok has shoes that use DMX technology!
> http://corporate.reebok.com/en/about_reebok/faq_section/technology/default.asp#What is DMX Foam?


 I have some of those shoes, they were great until one shoe deflated.


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## LXPlot (Jan 3, 2011)

shiben said:


> Wikipedia touches on this. Apparently it was a designation (sort of like you can get a Suburban XLT or whatever) from the original MFG.
> 
> XLR connector - Wikipedia, the free encyclopedia


 
I'm somewhat sure that this is correct after viewing edit history, there seems to be nothing that hints of vandalism or misinformation.


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## pathway (Jan 6, 2011)

Karl's little ditty was all about using terminology that supports our expectation of interoperability between different lighting products.

For example, if I as a consumer of lighting technology want to rent or buy a rig of gear, I'd be asking for trouble if I simply stated that everything needs to be DMX compatible. I might receive products that use 3-pin XLR's or even RJ45's instead of the mandated 5-pin XLR. I could get products designed by audio experts, who often prefer using analog op-amps or comparators as DMX receivers instead of the specified RS485 compliant digital devices. I might get products that have no signal common connection, or no opto-isolation. And I shouldn't be surprised if the installer uses whatever type of cable he has lying around the shop, and grounds all the shields because isn't that what you're supposed to do with shields?

At my company we've seen and continue to see all the above, and lots more, on a regular basis (all passed off as DMX compatible), and we spend a lot of time and effort helping users sort out malfunctions or worse in their lighting rigs, caused by people who prefer to do things their own way instead of following some arbitrary "standard".

The point Karl was trying to get across is that we have standards (developed at great trouble and expense I might add) to ensure that lighting systems work reliably and users don't get to pay the price for some manufacturers' ignorance or tendency to cut corners. Obviously it's no problem to say "run DMX to that light", but in any kind of documentation we should use the correct terminology, e.g. DMX512/1990 or DMX512-A (add the E1.11 2008 if you like), because it stipulates exactly what we're promising to deliver or expecting to receive.


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## pathway (Jan 6, 2011)

A minor (red-faced) correction to my previous diatribe is in order:

I implied that RJ45 connectors shouldn't be used for DMX512, but in fact the current (DMX512-A) standard allows them to be used in certain situations, and my company even makes DMX512 products with RJ45's. I meant to say "RJ11's" (the telephone jack).

But since I'm on the subject, I should point out that there at least three different RJ45 pinouts in common usage for DMX512 (including the standard one), so as usual it's buyer beware.


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## xander (Jan 6, 2011)

pathway said:


> ...but in any kind of documentation we should use the correct terminology, e.g. DMX512/1990 or DMX512-A (add the E1.11 2008 if you like), because it stipulates exactly what we're promising to deliver or expecting to receive.


I totally agree with you there. In manufacturers' and installation documents, it an absolute necessity that correct terminology is used, just as one would expect *ETC Source4 36** as opposed to *ERS* or *ellipsoidal*. However, with the following examples:


pathway said:


> I could get products designed by audio experts, who often prefer using analog op-amps or comparators as DMX receivers instead of the specified RS485 compliant digital devices. I might get products that have no signal common connection, or no opto-isolation. And I shouldn't be surprised if the installer uses whatever type of cable he has lying around the shop, and grounds all the shields because isn't that what you're supposed to do with shields?


None of these things are any more *DMX* compatible than they are *DMX512-A* compatible.

In my opinion, saying DMX is implying a standard. Which standard is vague as it has been revised. That's why when you are installing or researching equipment you need to be specific. But, in everyday use, DMX is a protocol that uses RS-485 transmitters and receivers on a 120 ohm, low capacitance, shielded twisted pair cable. Regardless of which revision.

Thoughts?
-Tim


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