DMX through Clearcom

[hhslights]

At our school we have a built in two channel clearcom system. It works wonderfully and we only use one channel for shows and everything else. Unfortunately though, we do not have a built in DMX system. We currently have cabling running through the length of the house from the light board to backstage. We use three prong cabling for our fixtures and it got me thinking a bit. Could we use an unused channel of our clearcom system to channel the DMX? I am still a bit new to the whole concept of intels and DMX but this seems like it might work. Has anyone done this before, or else in theory is it good? Would a belt-pack have to be constantly broadcasting on one end, both or neither? I don't know if we would end up using it but it would be nice to have the option to have an intel anywhere without having to run miles of cable.

[Van]

No, no, no, and no. You will find a lot of info on DMX all over this forum, search it. You would be better off pulling a piece of CAT5e through the conduit your clear com wire is run and installing a DMX compatible wall plate on each end.
The debate has raged here and other other places about running DMX over Mic cable. and the answer is Yes you can, no you shouldn't. Now in addition to that, the way your question is worded it sounds as if you are talking about plugging the 3 pin XLR from a light board into the input side of a belt pack and actually trying to run the DMX signal through the Clear com system, this again is a NO. The clear com system has power supplied through the cabling, you would, most likely fry your board and your dimmer control module. The five wire pins on a clear com set are a completely different animal < pin-out wise> than the DMX 5 Pin XLR. PLease don't even think about trying to plug them into each other. Heartache and badness will follow. Do some reading on here, get some of the recommended books on DMX, then look back at this post, shake your head, and say " I remember when I thought I could ...."

[cprted]

The problem lies in that DMX doesn't really like being sent down audio lines (which is typically what is used for clear com) for long runs. You could give it a shot, but make sure all your comm gear (including the power supply) is disconected from channel B.

If it were me, I would just leave it as it is or perhaps find an alternate route for the DMX if it bothers you that much.

[abbyt]

Short answer? No...won't work.

Don't have time for the long drawn-out explanation right now...walking out the door, but the few major things prohibiting this are, in no particular order:

1) Installed Clear-Com cable type is probably not DMX spec

2) Clear-Com sends voltage down the line (30VDC???) that wouldn't be good for your DMX devices

3) Clear-Com (and other similar listen/talk devices) are not capable of receiving and transmitting your DMX signal.

IF you have an entirely separate 3 pin line (dedicated FOR your Clear-Com but in NO WAY connected to any Clear-Com devices), and though you're probably dealing with low impedence (non-DMX spec) cable, then this MAY POSSIBLY work, though no guarantee of show-critical reliability.

You'd likely be better served investing in a wireless DMX system of some sort, should your budget permit...

-Abby

[cprted]

Originally Posted by Van

The five wire pins on a clear com set are a completely different animal < pin-out wise> than the DMX 5 Pin XLR. PLease don't even think about trying to plug them into each other.

In fact, the five/six pin XLR plugs on clearcom gear is designed so you actually can't plug DMX into it.

[Thefoxygranpa]

Originally Posted by abbyt

Short answer? No...won't work.

Don't have time for the long drawn-out explanation right now...walking out the door, but the few major things prohibiting this are, in no particular order:

1) Installed Clear-Com cable type is probably not DMX spec

2) Clear-Com sends voltage down the line (30VDC???) that wouldn't be good for your DMX devices

3) Clear-Com (and other similar listen/talk devices) are not capable of receiving and transmitting your DMX signal.

IF you have an entirely separate 3 pin line (dedicated FOR your Clear-Com but in NO WAY connected to any Clear-Com devices), and though you're probably dealing with low impedence (non-DMX spec) cable, then this MAY POSSIBLY work, though no guarantee of show-critical reliability.

You'd likely be better served investing in a wireless DMX system of some sort, should your budget permit...

-Abby

Actually, with the price of Cat5 cable, it will be less to pull that as Van suggested than to get a reliable wireless DMX solution.

[mrb]

another thing: you dont know how the clearcom wiring is ran. If you have a straight piece of cable between two wallplates that *might* work. But if there are Tees and Wyes all over the wiring connecting multiple wallplates that will wreak havoc with your DMX signal.

[Sayen]

I disagree - in a school setting, give it a shot and see what happens. In a perfect world, absolutely no, but schools aren't perfect. Many people, in a bind, have used audio lines to send DMX and it does frequently work.

It depends on how your ClearCom is run. If it's just a regular audio cable run alongside the house snake, which is typical, then just disconnect the ClearCom to avoid the aforementioned power problems, and connect your DMX line from the board through a five pin to three pin adapter. If the line is really bad you'll see it in whatever device you're trying to control, and then you have your answer.

Alternatively, try hijacking one channel of your house snake, if you're not using them all. Before I had the budget to purchase DMX cable I did this frequently, and never had any noticeable problems.

No professional would recommend the setup, especially for show-critical elements, but if the budget is tight and you can live with the chance that your DMX device might do something weird during a live performance, at least try it and see what happens.

[Van]

I need to throw out something in light of Sayen's post.
What he is saying is, "Yes, you can use audio cable in a pinch". Considering the OP's topic I want to make absolutely certain that you understand you cannot, under any circumstances, plug your DMX control into the "Clear Com" system. "That will end in Tears", as my wife would say.
I have seen people use audio snakes as a DMX line before. Yes it can work. It's not recommended. Moving lights, and any other devices that are basically motor control via DMX will not like getting thier signal through an audio cable.

[venuetech]

Originally Posted by mrb

another thing: you dont know how the clearcom wiring is ran. If you have a straight piece of cable between two wallplates that *might* work. But if there are Tees and Wyes all over the wiring connecting multiple wallplates that will wreak havoc with your DMX signal.

if i attemted this in my space i would have untermnated dmx signal in every one of my many com outlets, if it worked at all, it would not work well.
best to have a point to point dedicated run.

.