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Y shaped DMX cable

Posted: June 15th, 2009, 2:25 am
by dmxlighting
Make a special DMX cable ie 5pin or 3pin from your desk / dongle to 2 x 5pin or 3pin.
Wire your input as normal (probably pin3 hot) then on the other 2 ends, wire one as pin2 hot and one as pin3 hot.
This is most handy when testing unfamiliar fixtures. Saves hunting out a converter cable.

(note - I do not recommend using both ends at the same time, it might work but it shouldn't and can cause problems)


(female)XLR Pin2 Hot (female)XLR Pin3 Hot
\ /
\ /
\ /
\ /
(male)XLR Pin3 Hot

The diagram has not come out correctly, Ill post it as a jpeg at some point

Re: Y shaped DMX cable

Posted: June 15th, 2009, 2:29 pm
by remco_k
Or just use the familiar phase inverter adapter from Neutrik: NA3FMX
http://www.neutrik.com/us/en/audio/210_ ... etail.aspx
Image

Or easily create one of those youself. With an XLR Male and XLR Female with a small piece of wire in between, and cross pins 2 and 3.
So:
XLR-M---->XLR-F
PIN 1------>PIN 1
PIN 2------>PIN 3
PIN 3------>PIN 2

Making an Y connector should work just as good, but ONLY use those in controlled test situations, not in live situations. As the Y-adapter is not conform the standard and signal reflections may* occur bigtime, causing your other fixtures to fail or "misfire".

Then, if you (think you) need a phase flip, use this NA3FMX phase converter and you're safe to use it live.
Using this inverter also does'nt look "strange" to other technichians, where the Y-phase-inverter-adapter does.

* I say "may" because the chance for errors is somewhat unlikely if you leave 1 of the 2 ends open and if that end is nothing more then like 10 CM / few inches of loose cable. Don't(!) make a long cable on that ending in nothing, or as said, don't connect both "outputs" to DMX equipment.

Furthermore, I read over and over again about converter cables.
I guess people mean that that particular DMX cable is crosswired as I noted before, only the cable is not about 10 CM (or an adapter, like the NA3FMX) but a cable with longer length to run from 1 fixture to another?
I think no one should be using these XLR cables, as I find it may be confusing. My opinion is: "An XLR cable used to interconnect equipment should always be an 1:1 cable", if not, people using them will be in error one of these days.
If you need a phase flip, attach an extra converter in between like one of the 3 options above. So if someone else lookes at your setup, he (or she :mrgreen: ) immediately sees that you are using some kind of converter for some reason.
If you were using the phase flip cable (marked or not), it may be overlooked that its a phase flip cable, with errors to occur because of that.