DMX over Cat 5 -vs- 18 gauge speaker wire

[jerrymac]

Any reason dmx data shouldn't work over 18 gauge 4 conductor speaker wire (insulated like the wire used in the waterproof connectors). I am having some unusal issues and don't know if it is my connections or charastic of no twisted wire. I am sending the dmx data over cat 5 over a 100 foot wire and connecting to 40 feet of 18 gauge insulated speaker wire with power injected then, tapped off in 8 places for dmx controllers. (trunk line with t's soldered at each of the taps). ( sending 12 volt over two of the 4 wires and DMX over the other 2). Would it be likely or posible that the voltage is creating RFI interfering with the dmx data, or failure due to non twisted data wire ???

Edited December 19, 2012 by jerrymac

[rmturner54]

Jerry, I just got into dmx this year. I converted 4 North pole lights(the globes) to dmx using the 3 channel decoders. I contemplated a lot over this same subject. I am using 4 cond outdoor speaker wire i purchased from mono price. 2 cond for 12V and 2 cond for dmx. i am using a enttec pro dongle.I am also using the 4 cond waterproof male/female connectors. i have had no issues at all. My yard is quiet small and my total lenght of cable for this is approx 75ft. I also made every attempt to keep this cable away from my power cords and ac output channels.

[rmturner54]

I started early this summer and tested this setup for months to make sure there were no glitches. I just didnot like the idea of standard cat 5 connectors out in the elements.

[rmturner54]

My show ran all year with out a single glitch....rain or shine. Thats was using the waterproof connectors and speaker cable.

[Dennis Cherry]

My shows have run without glitches since 2008 using regular Cat5 cables.

[plasmadrive]

There are certain specs for DMX cables such as max capacitance, impedence, how to do the taps and total length... however.. with that said, DMX is RS485 which is a pretty robust communication protocol. You can get away with a lot if you are lucky and you don't pick up noise from other sources.. Since it is a differential input, most noise is self canceling if the wiring is flat or properly twisted such that the noise is picked up by both wired exactly the same.

So, the bottom line is that if it works for you, don't sweat it, you probably won't hurt the system as long as you don't have shorts or spikes of voltage/noise. Watch for anomalous triggers on your lights...