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[David Allred]

1- If a unit is powered off (or dead) will units downstream receive the MDX signal?
2- Are there any electronics directly between the input and output connectors?
3- Will a unit be able to receive the DMX info thru the output connector (male to male DMX cable from controller) and then send info out the input connector to the next unit's input connector (female to female DMX cable)?  I am not wanting or needing to do this (#3)... just a thought exercise.

Thanks,
David

[Jeff Lelko]

Hi David,

See the attached PCB for some insight on how most DMX I/O circuits work.  This leads to the following answers to your questions:

1 - Yes, so long as the dead unit isn't leaking/leaching power or logic level voltage on the DMX I/O circuit that corrupts the signal.

2 - Usually not, though there are exceptions.  Most DMX devices are not signal repeaters.

3 - Usually yes, and if the I/O board is as the example you can convert 3-pin to 5-pin across the unit as well.

Hope this helps!

 

[Brian Jojade]

+1 with Jeff on this. Yes, generally DMX ins and outs are just paralleled.  There's a short amount of wire then that goes to the DMX electronics.

It's actually possible to split a DMX signal passively, although when you do that you run into the risk of unexpected reflections, data errors, etc.

Now, some devices do have active splitters inside them, which then is totally a different scenario, but these are typically specialty items that most won't run into.

One case where this can cause you major issues is when using wireless DMX.  Some wireless DMX receivers will turn themselves into transmitters if they see a DMX signal.  If one of your lights gets put into master mode, it sends out a signal, confuses the receiver, and well, nothing works.  Fun times.

[David Allred]

Thanks, guys. 

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