# 7-pin DMX



## pudgeo2 (Nov 17, 2007)

So I've been working in a shop for a large AV company. I was doing some house cleaning, when I came across a box of 6 & 7 Pin DMX. I know what 6 pin is used for (analog dimmers & RFUs), but does anyone know what 7-pin is used for?


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## JD (Nov 17, 2007)

By DMX, you mean the old Canon style connectors? (XLR) 

As far as I know, DMX is only in 5 and 3 pin styles, but the Switchcraft / Canon / Neutrik connectors come in many configurations. 7 pins might be handy for 6 channel analog dimmers among other things. (6 chns & common, so you don't use the shell.) So, maybe they have been there for awhile.


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## gafftaper (Nov 17, 2007)

True DMX standard should have 5 pins and only 5 pins. Two of those pins usually aren't used. Sometimes manufacturers cut it down to three pins. Sometimes power is added and you have four pin scroller cables. But that's just messing around with what is convenient for their products. Seven Pin? My guess is that it's some sort of pre-dmx proprietary control cable or an analog cable as pointed out already. There was some time between analog control and when the DMX standard was adopted were every manufacturer had it's own sort of digital control. Another possibility is some sort of modern adaptation to make the old technology work with current cable?

If you find an old Cinch Jones cable you'll see about 20 pins. They have a rectangular plug. Remember in the "bad old days" before DMX you needed a separate wire for every dimmer you were controlling.


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## icewolf08 (Nov 17, 2007)

Yes, the DMX512-1990 standard requires you to use a 5 pin connector and 5 conductor cable. There was talk about being able to expand the protocol for other uses that hasn't happened yet. Manufacturers realized that since only 3 of the 5 pins were being used they could save money by using 3 pin connectors and 3 pin cable. In many new devices you have both 3 and 5 pin connectors, so some manufacturers decided they would spend extra money, but the end user pay it anyway, so who cares.

Is DMX due for an overhaul? Probably not. There is ACN which is starting to hit the market, but it is going to take a very long time before DMX goes away. DMX does just about everything we need it to do, and it has been installed in so many venues that upgrading will take a very long time. There are still people using analog dimmers that require Cinch Jones connectors, and they just hook their new console up through an A/D converter.

The reason that DMX is not used for triggering scenery or Pyro cues is due to the protocol itself, and has absolutely nothing to do with the physical properties of the cable, etc. DMX is based on the RS-485 data protocol. The controllers sends out a repeating stream of information, consisting of a start code, and then 512 data blocks which are the levels for the 512 DMX "channels" that can be connected to one universe. Each device in the universe counts the blocks as they go by, and if the devices starting address is 100, it listens to block 100 through whatever and does what it is supposed to do. DMX has no error checking though, so if there is a bad block and it was connected to a pyro device, it could accidentally trigger the device. This is why protocols like MIDI are used for show control.


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## SteveB (Nov 17, 2007)

pudgeo2 said:


> So I've been working in a shop for a large AV company. I was doing some house cleaning, when I came across a box of 6 & 7 Pin DMX. I know what 6 pin is used for (analog dimmers & RFUs), but does anyone know what 7-pin is used for?



Can't remember exactly, but it might be either ETC RFU cable (I think that's 6 pin XLR), or possibly Sensor to Console Link cable. Not sure why you would have Link cable in anything over 20ft, which would be sufficiant to go from a booth wall plate to a console, as generally it's hard wired to the racks. Might be for a touring system that wanted the Link system operational. 

SB


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## sound_nerd (Nov 17, 2007)

We use 7 pin xlr style connectors on all of our 6ch analog packs and controllers. It is much more durable than the midi type connectors that came standard on the packs. (LDS DS-3000 systems)

The 6 pin? I have no idea.


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## Footer (Nov 17, 2007)

sound_nerd said:


> We use 7 pin xlr style connectors on all of our 6ch analog packs and controllers. It is much more durable than the midi type connectors that came standard on the packs. (LDS DS-3000 systems)
> The 6 pin? I have no idea.



Could also be a 2 channel com system cable. Telex has 6 pin on all of there 2 channel packs.


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## icewolf08 (Nov 17, 2007)

6-Pin is generally used as RFU cable, and 2 channel Clear-Com.


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## len (Nov 17, 2007)

To be excruciatingly precise, the ONLY cable that is truly dmx is 5 pin twisted pair shielded. This according to the USITT standard updated a couple years ago. 

4 pin scroller cable is not dmx, although it is used in lighting. As is 3 pin xlr, and perhaps 6 or 7 pin. Or cinch-jones. And all the others. Theoretically, 3 conductor extension cords could carry dmx data. So while it is possible that any cable carries a dmx signal it is not truly dmx standard unless it is 5 pin xlr twisted pair shielded cable.


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## Footer (Nov 17, 2007)

len said:


> To be excruciatingly precise, the ONLY cable that is truly dmx is 5 pin twisted pair shielded. This according to the USITT standard updated a couple years ago.
> 4 pin scroller cable is not dmx, although it is used in lighting. As is 3 pin xlr, and perhaps 6 or 7 pin. Or cinch-jones. And all the others. Theoretically, 3 conductor extension cords could carry dmx data. So while it is possible that any cable carries a dmx signal it is not truly dmx standard unless it is 5 pin xlr twisted pair shielded cable.



The loop hole to the standard was that the manufactuers could put 3 pin on and call it DMX if they supplied an adapter, so people just put on the 3 pin and forgot about supplying the adapter. The real deal was that production houses did not want to stock an extra cable when they had plenty of 3 pin connectors and cable laying around.... even though hardly any of it was meant for data. 

Before anyone says it... RDM was originally thought to use the second pair but because so many fixture don't have access to the second pair they were able to cram RDM into the first pair along with DMX data.

It has also been said that you can run DMX through a barb wire fence... would you want to... no... but you could.


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## derekleffew (Nov 17, 2007)

Should anyone ever need to order 6pin XLR plugs and connectors, be aware there are *two* pin configurations, and they are not compatible with each other. One has the pins arranged symmetrically, the other does not. I believe the ETC RFU (Expression family) uses the non-symmetrical, and Telex and CLearCom use the symmetrical, but I might have that backwards.


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## Footer (Nov 17, 2007)

derekleffew said:


> Should anyone ever need to order 6pin XLR plugs and connectors, be aware there are *two* pin configurations, and they are not compatible with each other. One has the pins arranged symmetrically, the other does not. I believe the ETC RFU (Expression family) uses the non-symmetrical, and Telex and CLearCom use the symmetrical, but I might have that backwards.



Doesn't the RFU have 6 pins but one pin is a center pin? I haven't have an ETC RFU for a few years so I can't really remember. I also remember the ETC link cable having a center pin or two. I do know that you can plug the DMX cable into the RFU output on ETC consoles, that tripped me up a few times when I let someone else run the DMX...


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## JD (Nov 17, 2007)

charcoaldabs said:


> What are the biggest disadvantages with DMX?
> I know it has something with data / shielding / something that makes it unusable for automation / pyro control.



The biggest disadvantage to DMX is that it works like a boss shouting orders who doesn't listen to anyone! If someone doesn't hear him right, they go out and do the wrong thing! (Thus BAD for Pyro.) Technically, this is known as "error check" which DMX does not have. As far as the extra pins go, people who write standards like to allow for things that sometimes don't happen. Ethernet has 8 pin connectors, and 8 conductor cabling but only uses 4 wires. So, some have adopted a 3 pin system with DMX and it works fine if you are using all 3 pin fixtures. Others have used the second pair for a second DMX universe, doubling the amount of channels it can handle. But it was said before. The standard is 5 pin, and anyone who uses the extras to do something like feed power is no longer on the standard, and probably asking for trouble!


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## Logos (Nov 17, 2007)

European Phillips audio gear used to use the Din plug with 7 pins and upgraded that at one point to the same size as a Canon 3 - 6 pin. It wasn't very popular. It was a real [email protected]#$%^d to solder.
Riggers units on ETC boards used a 6 pin Canon plug for a couple of models. I think that has already been mentioned. 
Wasn't there a video application that used 7 pin Canon plugs in the sixties or seventies.


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## kwotipka (Nov 17, 2007)

gafftaper said:


> If you find an old Cinch Jones cable you'll see about 20 pins. They have a rectangular plug. Remember in the "bad old days" before DMX you needed a separate wire for every dimmer you were controlling.



I hated those things.


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## gafftaper (Nov 17, 2007)

It's been touched on but not really clearly... The original purpose for those two extra pins was for information from the device to be returned back to the console. There are a few applications where this is going on right now but EXTREMELY limited.

As for the future of DMX. It is on the way out BUT it will be VERY slow. ACN and Ethernet based control is coming very soon. While we wait for ACN to be fully adopted we are in a period of proprietary ethernet languages. New Consoles have been coming out with both ethernet and DMX jacks for a year or two... I believe EOS is the first to ONLY have ethernet jacks (right?) I'm not sure what intelligent gear has ethernet jacks just yet but it won't be long until it all does. There are a lot of advantages to the user of ethernet based control, #1 being the cable is far cheaper. 

My new theater is Strand based so it will "talk" Strand's proprietary ethernet language from the console to the dimmers and back. The Strand language goes out over the ethernet system of the theater to the DMX nodes. The nodes translate it into DMX and from there it's DMX cable to my gear. In the future my console and dimmers will be upgraded to speak ACN If I am able to purchase gear that speaks ACN there will be no need for the nodes, or the expensive DMX cable. Everything will speak ACN and connect via ethernet cable. 

To me, the best part of the future is RDM. With RDM we will no longer need to set DMX addresses. The gear will identify itself to the network and talk back to the console. You'll be able to plug in a bunch of gear hit a button and it will all find itself in the network. Much like plugging in a USB device to your computer today. 

When will we all have ACN? About the time Charc retires. ACN and RDM are realities that will be implemented soon. The technology is here and the manufacturers just have to go through the process of implementing it. However the question is, can your theater afford to switch when your DMX system is working just fine? Yeah that's what I thought. My guess is in about 5 years the vast majority of new purchased gear will no longer be DMX based. Gradually as systems go down ACN will replace DMX. So it'll take a good 15-20 years until most of us make the switch to ACN. Then it'll be another 15-20 years after that until the "cinch jones" club (little community theaters, schools, and churches) give up their ancient gear and upgrade to ACN equipment. DMX is dead technology... but she's going to take a *REALLY *long time to die so get used to her.


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## icewolf08 (Nov 17, 2007)

charcoaldabs said:


> What do we think about the possibility of ACN and data in general being delivered wirelessly inside a venue? No need to connect anything besides power. I see the clear advantages of wires over wireless whenever possible, but I think it'd be an interesting idea. This one is pretty stupid, but what if data and power were integrated into a single connector? That would be kinda weird...



Though wireless is nice, it is kind of moot since you need to run power to the fixtures anyway, though I suppose we do have W-DMX...

As for power and data in the same cable, for moving lights it is probably a bad idea. A mis-wired scroller cable can cause hundreds of dollars of damage. A mis-wired high voltage/data line would cause thousands of dollars of damage, and maybe some unwelcome pyro effects.


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## avkid (Nov 17, 2007)

icewolf08 said:


> As for power and data in the same cable, for moving lights it is probably a bad idea. A mis-wired scroller cable can cause hundreds of dollars of damage. A mis-wired high voltage/data line would cause thousands of dollars of damage, and maybe some unwelcome pyro effects.


Yeah, many people have tried power and data in the same cable for several different applications.
I don't care what people say about PoE and it's possibilities, I am still not comfortable feeding my lights or computers with it.
There's just something about electricity and 23 AWG copper that doesn't give me the warm fuzzies.


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## Footer (Nov 17, 2007)

gafftaper said:


> It's been touched on but not really clearly... The original purpose for those two extra pins was for information from the device to be returned back to the console. There are a few applications where this is going on right now but EXTREMELY limited.
> As for the future of DMX. It is on the way out BUT it will be VERY slow. ACN and Ethernet based control is coming very soon. While we wait for ACN to be fully adopted we are in a period of proprietary ethernet languages. New Consoles have been coming out with both ethernet and DMX jacks for a year or two... I believe EOS is the first to ONLY have ethernet jacks (right?) I'm not sure what intelligent gear has ethernet jacks just yet but it won't be long until it all does. There are a lot of advantages to the user of ethernet based control, #1 being the cable is far cheaper.
> My new theater is Strand based so it will "talk" Strand's proprietary ethernet language from the console to the dimmers and back. The Strand language goes out over the ethernet system of the theater to the DMX nodes. The nodes translate it into DMX and from there it's DMX cable to my gear. In the future my console and dimmers will be upgraded to speak ACN If I am able to purchase gear that speaks ACN there will be no need for the nodes, or the expensive DMX cable. Everything will speak ACN and connect via ethernet cable.
> To me, the best part of the future is RDM. With RDM we will no longer need to set DMX addresses. The gear will identify itself to the network and talk back to the console. You'll be able to plug in a bunch of gear hit a button and it will all find itself in the network. Much like plugging in a USB device to your computer today.
> When will we all have ACN? About the time Charc retires. ACN and RDM are realities that will be implemented soon. The technology is here and the manufacturers just have to go through the process of implementing it. However the question is, can your theater afford to switch when your DMX system is working just fine? Yeah that's what I thought. My guess is in about 5 years the vast majority of new purchased gear will no longer be DMX based. Gradually as systems go down ACN will replace DMX. So it'll take a good 15-20 years until most of us make the switch to ACN. Then it'll be another 15-20 years after that until the "cinch jones" club (little community theaters, schools, and churches) give up their ancient gear and upgrade to ACN equipment. DMX is dead technology... but she's going to take a *REALLY *long time to die so get used to her.



Whats going to kill people with ACN is the fact that you can't daisy chain but have to do a point to point for each fixture. Couple that with the 300' limitation and there are going to be some issues. Fiber snakes will become the norm simply because they will have to. I HIGHLY encourage anyone who is wanting to get into any type of technical theatre to go get their CCNA. I should have mine (took the class, never had the time to take the test.... or I am just lazy.. you pick). I can not tell you how much having that class has helped me. When these networks get larger data systems are going to have to grow. I see in the future a gigabit fibre backbone going to each truss breaaking out into cisco switches that will take copper to the fixture. Ethercon connectors on everything... yadda yadda yadda. 

Also remember that HIGH QUALITY (Cisco...) switching gear is expensive. More then any opto-splitter. You can get cheap off the shelf switches for a few hundred, but the odds of it going down are pretty good. Very little of this stuff is meant for the road so things will have to be beafed up. Cisco designs most of their gear to get racked up in an air conditioned room and turned on and left on for 10 years. We do the exact opposite. We put things on a case, plug and unplug it hundreds and hundreds of times, throw the case in a 5 degree below zero truck, let it bounce around, pull it out at 6am, plug it in, and repeat. Common networking gear will break by the 3rd show. The cost of having a switch for every 24 or 48 fixtures is not going to be cheap, and people are going to be very slow to make the investment if DMX is still around. Ethernet works great for distrubution, I have 4 SN110 nodes on the show I am doing right now. When ACN gets to the actual fixture, things are going to get much more complicated. 

Clay Packy is now putting "future ethernet" jacks on all of their new Alpha wash/Alpha Spot gear, thats the first ones I have noticed. Many other companies are soon to follow. I see DMX jacks staying on most gear for at least the next 10 years. After all... there are still AMX jacks on the ETC 12 and 24 Packs and AMX died nearly 15 years ago. We still have serial jacks on our computers... these protocols never really die... they just fade away VERY slowly.

oh... and I want the update for the SN110's for ACN to come out... NOW.


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## kwotipka (Nov 17, 2007)

I have a question. Is this new control system true TCP/IP or UDP data? There are lots of video protocols out there for video that pass over CAT5 but is not legal network traffic. Problem is that TCP/IP has tons of overhead that delay the signals. I don't know if lighting is that picky. If it is TCP/IP, how may channels can you load this thing up with before it becomes an issue. It obviously isn't UDP because there is no error correction in that and you are back to the issues of DMX there.

just wondering.

kw


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## derekleffew (Nov 18, 2007)

As has been stated before, DMX over Ethernet is still proprietary to each individual lighting manufacturer. While the most common Art-Net, freely open licensed by Artistic Licence is true TCP/IP, every manufacturer recommends only lighting being on any one network. ACN is supposed to change that, but I'm still not convinced running pyro, motion control, or any other life safety/mission/time critical data being run over ethernet is a good thing. Art Net supports up to 64 Universes of 512 channels each, and the grandMA has been tested up to that, via 16 NSPs. The September issue of _Lighting&SoundAmerica_ has an excellent article on ACN and ETC's implementation, by John Huntington, author of _Control Systems for Live Entertainment_, Third Edition. Focal Press, 2007. (Shameless plug for my friend John).

Gafftaper, the new Martin Stagebar54 LED striplight has only RJ-45 connectors, but currently is a DMX-only fixture. So you need an A5M-to-RJ45 adaptor at the beginning, then you can daisy-chain using CAT5 cables, then need an RJ45-to-A5F at the end to terminate or continue to standard moving lights. ColorKinetics/Phillips ColorBlaze48 and 72 striplights allow you to use all CAT5 cables, but only with a proprietary controller.


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## derekleffew (Nov 18, 2007)

icewolf08 said:


> As for power and data in the same cable, for moving lights it is probably a bad idea. A mis-wired scroller cable can cause hundreds of dollars of damage. A mis-wired high voltage/data line would cause thousands of dollars of damage, and maybe some unwelcome pyro effects.


Are you forgetting VL Series 200 cables, commonly known as "superlamp" and PRG's S400 series (where power and data runs through one multi-cable)?


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## icewolf08 (Nov 18, 2007)

derekleffew said:


> Are you forgetting VL Series 200 cables, commonly known as "superlamp" and PRG's S400 series (where power and data runs through one multi-cable)?


Ummm... Yes... I have never worked with them, and I won't now for fear of blowing them up!


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## derekleffew (Nov 18, 2007)

icewolf08 said:


> Ummm... Yes... I have never worked with them, and I won't now for fear of blowing them up!


Well, many would say there are many worse things you could do besides "blowing up" a series 200 fixture, or module. As to the S400, it's actually idiot proof. Plug an L6-20 box into a 120V module and it won't pass power. Likewise with an Edison box plugged into 208V. I've seen a few times when a conventional Socapex-type multicable got plugged into a 208V moving light distro instead of a dimmer rack--the lamps are really bright, but not for very long. The worst was when a show lost 6x CYX 2Kw Fresnel lamps, and the spares package only included 3! Oops. "I swear it wasn't me, I told _you_ to label the cable..."

I learned/remembered today that Versatubes use symmetrical 6pin XLR for certain data runs. Also Load Cells used in rigging.


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## STEVETERRY (Nov 18, 2007)

icewolf08 said:


> Is DMX due for an overhaul? Probably not.


We just did a major overhaul in 2004. The standard is now called:

*ANSI E1.11-2004--Entertainment Technology - USITT DMX512-A - Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories*

Couple that update with the approval of another standard last year:
*ANSI E1.20 - 2006--Entertainment Technology--Remote Device Management over USITT DMX512*

and one can imagine that DMX512 is a thriving standard that is not going away at all!

Why?

Network connectivity like ACN is not suitable for all types of target equipment. The reasons vary:

1. Not enough processing power for full ACN in small, lightweight products (fog machines, scrollers, etc)
2. Ethernet network topology may not be friendly to a particular application. For instance, it may be preferable to daisy-chain DMX devices rather than use the mandatory star configuartion of Ethernet.

So, how do we deal with that? A very good topology uses ACN gateways, with multiple DMX/RDM outputs. This allows DMX/RDM to be used as the "last mile" short-haul connection. Rather than using opto-splitters (which now need to be bi-directional and intelligent to turn the DMX data link around for RDM), we move onto the ACN network through a gateway. This device allows many of the features of ACN to be used on non-network DMX/RDM devices.
Finally, there's another draft standard everyone should know about, that is about to go into second public review:

*BSR E.1.31--Lightweight Streaming Protocol for Transport of DMX512 using ACN*

This standard, sometimes known as Streaming ACN or sACN, gets us back to a very simple Ethernet protocol for moving DMX. It is simple enough that very lightweight embedded processors can handle it. Many ETC products speak this protocol already (Draft 1), and you can expect for it to become ubiquitous through out the industry. It offers significant advantages over ArtNet, since it is fully TCP/IP compliant and routable.

ST


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## JD (Nov 18, 2007)

Fiber optics... Two very nice things come to mind. 1) Glass does not conduct! 2) Something poetic about controlling lights with light. 

I like the concept, and Ethernet over glass is a pretty worked out concept. There is one downside... Ever splice glass? I have. It's a pain in the you know where! Welcome a new tool into our toolbox; The Cleaving tool! I suspect all cables will be pre-made for awhile. There's more good on the upside; Thanks to Verizon and other FIOS labs, there is almost no length limit to the cable. Run it from your board, out around the football stadium, and then up to your truss if you want. Also, you can overdrive a fiber and passively split it several hundred times. In other words, one fiber hits a truss and goes into an passive optical splitter and feeds 124 lights. Nothing needs to have power, and optical splitters don't crash. The technology is well proven. I am on a FIOS link right now. I am at the far end of a seven mile glass fiber that has been split 15,376 times. (124 x 124 two descending splits) Those little brown boxes out on the poles are the passive optical splitters. (no electronics.) And yes, the data can go both ways or I would never be able to upload anything! Another alternative would be the backbone split. Much like the standard DXM, each fixture could be looped. Light does not care how it is split so having a passive splitter in each light would work as well. With a hot fiber, you could again chain many fixtures without concern of order. There's a lot of options. 
I am glad to see TCP/IP protocol is being used for the BSR E.1.31 There is an entire world of options out there if you are using it. If the developers of a new standard do not use it, we should check for the presence of a Swiss bank account because someone paid someone off!


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## Footer (Nov 18, 2007)

JD said:


> Fiber optics... Two very nice things come to mind. 1) Glass does not conduct! 2) Something poetic about controlling lights with light.
> I like the concept, and Ethernet over glass is a pretty worked out concept. There is one downside... Ever splice glass? I have. It's a pain in the you know where! Welcome a new tool into our toolbox; The Cleaving tool! I suspect all cables will be pre-made for awhile. There's more good on the upside; Thanks to Verizon and other FIOS labs, there is almost no length limit to the cable. Run it from your board, out around the football stadium, and then up to your truss if you want. Also, you can overdrive a fiber and passively split it several hundred times. In other words, one fiber hits a truss and goes into an passive optical splitter and feeds 124 lights. Nothing needs to have power, and optical splitters don't crash. The technology is well proven. I am on a FIOS link right now. I am at the far end of a seven mile glass fiber that has been split 15,376 times. (124 x 124 two descending splits) Those little brown boxes out on the poles are the passive optical splitters. (no electronics.) And yes, the data can go both ways or I would never be able to upload anything! Another alternative would be the backbone split. Much like the standard DXM, each fixture could be looped. Light does not care how it is split so having a passive splitter in each light would work as well. With a hot fiber, you could again chain many fixtures without concern of order. There's a lot of options.
> I am glad to see TCP/IP protocol is being used for the BSR E.1.31 There is an entire world of options out there if you are using it. If the developers of a new standard do not use it, we should check for the presence of a Swiss bank account because someone paid someone off!



You could just get a fusion splicer... for around 15 grand. We had 2 at where I used to work (the company mainly installed fiber). They are rather amazing to watch.


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## ship (Nov 19, 2007)

There is two types of 6-pin cable, Neutric standard as I call it and what is industry for Switchcraft standard. One of the two - forget which is about 20 degrees off center from pins aligned to on center. Dual channel Clear Com for instance will use the Switchcraft Standard plug - though it as opposed to Link does not use all the pins (even Neutric will have a code such as NC6-FPs in the last digit recognizing “switchcraft standard.”), other things that use it are ETC Link system and Motion Labs motor/hoist control sensor cable which uses the opposing system.

On seven pin cable, that’s a newer type of plug for something my memory doesn’t serve me on but I stock for some very new type of control system. Very modern in use if XLR plug type in style - only came out in the last few years.

Having to stock all these types of cable/plug is a pain in the rear but there really is a 7-pin XLR cable/plug.

By the way - on the concept level at least... 5-pin DMX cable will work for dual channel Clear Com systems. Break off the center male pin on what ever is using 6-pin on the clear com and a 5-pin DMX plug will fit and work fine with it.


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## Conner8809 (Oct 11, 2008)

5 pin dmx is used to seperate 2 different universes. you simply split them into 2 three pin dmx cables on both ends. and bam you have 2, 512 universes.


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## Sean (Oct 11, 2008)

Conner8809 said:


> 5 pin dmx is used to seperate 2 different universes. you simply split them into 2 three pin dmx cables on both ends. and bam you have 2, 512 universes.



Technically, no, but Lex makes something....

http://www.lexproducts.com/catalog/dataProducts/DataBrochure.pdf
See page 4 (actually page 6 of the .pdf)


--Sean


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## derekleffew (Oct 11, 2008)

Conner8809 said:


> 5 pin dmx is used to seperate 2 different universes. you simply split them into 2 three pin dmx cables on both ends. and bam you have 2, 512 universes.


The scheme you are suggesting is NOT in compliance with *ANSI E1.11-2004--Entertainment Technology - USITT DMX512-A - Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories. 

*Furthermore*, *can you name any manufacturer or device, with the exception of certain Avolites consoles (and the Lex#DMXUSS referenced above), that supports using pins 4&5 as an "alternate universe"? 

Another point: around here the consensus is there's no such thing as "three pin dmx cables." If XLR3 connectors/cables MUST be used to carry DMX, we call them "data" cables/connectors, not DMX.


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## church (Oct 12, 2008)

I have a number of 4 channel dimmer modlues that use 6 pin XLR for the analog control input. They use five pins in the same configuration s the 5 pin XLR and have a sixth pin in the centre. At least it stops anyone connecting a DMX signal to them.


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## jmabray (Oct 14, 2008)

Footer said:


> Whats going to kill people with ACN is the fact that you can't daisy chain but have to do a point to point for each fixture. Couple that with the 300' limitation and there are going to be some issues.


 

Ummm... why not put a two port switch on every fixture? 

Most of those issues go away then....


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## derekleffew (Oct 14, 2008)

jmabray said:


> Ummm... why not put a two port switch on every fixture? ...


One good reason: If (when) a fixture needs a hard-reset, every fixture downstream of it will lose data. Currently with DMX a fixture will pass signal whether it's on or off.


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## jmabray (Oct 14, 2008)

I am sure that can be overcome with the simple addition of a battery back up for the small switch. You wouldn't need it to last long, so it could really just be a board with some cap's on it.....


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## TimMiller (Oct 14, 2008)

OK, the hog III was the first console to come out with only eithernet on it. I was thinking the same thing as far as installing a small switch on the fixture, what if the switch is powered by PPOE, but you would have to implement it kind of weird system to where if the node is not powered up power will have to feed back down the line to the node that is not connected. And i have always kept systems with PPOE seperated from systems that do not require it becuase i have never looked into how a switch that does not support PPOE will take PPOE. I dont want to blow anything up.


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## fredthe (Oct 14, 2008)

Monor nit: it's POE (Power Over Ethernet,) not PPOE (sometimes used for Point-to-Point Protocol over Ethernet)
As for connecting unpowered devices to a POE switch, there should be no problem, as the switch autodetects if the device requires power. However, connecting two switches that are both capable of suppling POE together may be a problem.
-Fred


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## SteveB (Oct 14, 2008)

jmabray said:


> I am sure that can be overcome with the simple addition of a battery back up for the small switch. You wouldn't need it to last long, so it could really just be a board with some cap's on it.....



That is extraordinarily complicated and unnecessary. KISS is the object - Keep It Simple. Remember as well that many manufacturers cannot be bothered to even provide a 5 pin connector on their movers - High End comes to mind, still using 3 pin XLR, so what are the chances they are going to want to install an Ethernet switch PLUS battery backup !.

A post on this thread from last Nov. by Steve Terry well describes how Ethernet will go everywhere but the last mile, for good reason and there will probably still need to be either a DMX run on "5 pin DMX cable" from a node, or a different standard over Ethernet that allows daisy chaining fixture to fixture.

Steve B.


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## jmabray (Oct 14, 2008)

I really don't think it's that complicated, to be honest. With the advent of the new protocols, there is going to have to be some different things done. It will be interesting to see how each of the manufacturers deal with it, however.

If it is true that you still have DMX as the last mile, we would really be throwing out a lot of good features that ACN can be used for.... While RDM might make up for some of that, it won't do it all and then what's the point of ACN?


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## TimMiller (Oct 15, 2008)

SteveB said:


> Remember as well that many manufacturers cannot be bothered to even provide a 5 pin connector on their movers - High End comes to mind, still using 3 pin XLR, so what are the chances they are going to want to install an Ethernet switch PLUS battery backup !.



Most of highends gear comes with 5 pin dmx. The only exception are some of the older fixtures that were designed to run off of Lightwave Research Protocol (LWR), which was very close to dmx but used xlr. Those fixtures were the I-beam, Trackspot, and Studio Spot/Color 575. The problem now is if they were to switch to 5 pin on their studio spots it would be crazy trying to figure out data runs for a show wondering if some of the fixtures are 5 pin and others are 3 pin. At one time we had some studio spot 575's that were 5 pin, and it drove everyone crazy because they were odd balls.


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## jmabray (Oct 15, 2008)

Can we all be clear on something here?

XLR is the type of connector. There are 3 pin XLR (mic or an unapproved DMX), 4 Pin XLR (typically scroller), 5 pin XLR(DMX), 6 Pin XLR, (used for many things, but Clear-com is one), and by the title of this thread, 7 pin XLR.

XLR does not mean that it is a 3 pin connector. These connectors were originally called "Cannon X" connectors (after the guy that invented them) with the LR coming on through subsequent versions of the connector ("L" being the latching mechanism and "R" being the rubber compound between the pins) 

Sorry to gripe about this, but this is one of my pet peeves. Kinda like calling a lamp a bulb. Don't get me started on that one..... 

Is this picky? Absolutely. But as we are reduced to nothing but text in these forum type of settings, I think that it's pretty important that we try our best to be as accurate as possible. Thanks!


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## SteveB (Oct 15, 2008)

In a conversation this morning with ETC, they turned me on to a very elegant solution to getting multiple Cat5 taps at location. 

It's a device made by 3Com, called IntelliJack.

http://www.3com.com/other/pdfs/products/en_US/400717.pdf

Basically a PoE switch that can be mounted in a standard electrical box (think 1900 box with a c-clamp on it - or permanently mounted on/in a wall) and allows signal to 4 devices as well as pass thru. 

Nice stuff.

Steve B.


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## derekleffew (Oct 15, 2008)

jmabray said:


> Can we all be clear on something here?
> XLR is the type of connector. There are 3 pin XLR (mic or an unapproved DMX), 4 Pin XLR (typically scroller), 5 pin XLR(DMX), ...
> XLR does not mean that it is a 3 pin connector. ...
> Sorry to gripe about this, but this is one of my pet peeves. ...


You might start by convincing the world's largest lighting production company, who uses:
"XLR" to refer to any 3-pin data cable
"RAM" to refer to any 4-pin data + power cable, including LEDs
"DMX" to refer to any 5-pin DMX cable.


SteveB said:


> ...Basically a PoE switch that can be mounted in a standard electrical box (think 1900 box with a c-clamp on it - or permanently mounted on/in a wall) and allows signal to 4 devices as well as pass thru. ...


So I could just daisy-chain these gizmos (3com IntelliJacks) down the truss, one for each set of four lights? (When we have fixtures that support ACN, that is.) Before ship does, I'll object to your use of a 1900 box for such a purpose.


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## SteveB (Oct 15, 2008)

derekleffew said:


> So I could just daisy-chain these gizmos (3com IntelliJacks) down the truss, one for each set of four lights? (When we have fixtures that support ACN, that is.) Before ship does, I'll object to your use of a 1900 box for such a purpose.



From what I was reading in the 3Com literature - yes, you can daisy chain as one model seems to have an Uplink RJ45, a pass-thru RJ45 and 4 data RJ45's, thus 4 devices.

I have no info, but wonder if there are limits as to how far and how many devices before you exceed the capabilities of the PoE injector, though 3Com does have an AC adapter for the units and the devices can inject PoE directly and locally.

I'm also not sure exactly what box it fit's as it's designed for in-wall, so I assume either handy box or 4x4 of some sort. Then it just needs a c-clamp to pipe/truss mount. I would prefer a Woodhead box, but at this point these units are intended for an office environment, so the actual box, and robustness of the design needs to be thought about. What exactly about the 1900 didn't you like, BTW ? - (Or to put it another way - how am I being stupid - before I spec. it !)

Maybe something for Lex Products or City Theatrical to think about.

Steve B.


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