DMX Opto Splitter
The OPTO-Splitter allows a single DMX-512 line to be translated to a hub and spoke configuration. It optically isolates every Output from each other as well as the Input for ground fault isolation. The unit also provides a DMX Thru connection for insertion in the middle of a DMX chain. The THRU port is hardwired with the INPUT port and allows to daisy-chain the devices, even when it is not powered.
There is also a button that will act as a terminator, this should be used if you aren't using the thru port.
Uses
Allows you to send your DMX signal to different directions or more lights.
Also acts as a way to isolate the console from the lights, This is very important in case of any malfunctions. Lights can sometimes send rogue voltage down the DMX line. Most consoles do not protect against this, but a proper DMX opti-splitter will.
It is standard practice to put an opto splitter directly after your console and in the dimmer room, this will protect against any issues you may have since the ports are optically isolated from the dimmer packs. This will basically act like a limiter if anything greater than the normal signal is placed on the line. Placing Opto splitters at every Distro box is also very common as it gives you a way to patch in your DMX anywhere in your rig.
Even if not a total voltage-leaking failure (which is rare, but happens), many inexpensive lights will send out DMX signal if put into “stand-alone” or “automatic” mode, which will cause the rest of your lighting rig to flicker or be non-responsive, by not using chain network topography and instead using the hub and spoke method you will reduce the chances of affecting the entire rig and make it easier to troubleshoot.
Troubleshooting
If you’re not receiving DMX signal at your fixture, you should use a DMX troubleshooting device, such as a DMXcat to confirm you are receiving DMX values at the end of the run.
If your opto splitter is not working, confirm it has power and that it has a DMX line patched to the IN port.