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Old February 18th, 2015   #3
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Join Date: Dec 2014
Location: Sofia, Bulgaria
Posts: 2
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Hi Ericthegeek,

thank you very much for the comprehensive explanation! Sorry for my late response, but I had some hardware roadblocks to overcome.

There are some questions emerged after I reviewed your answers. For instance, what about DISC_UN_MUTE message which is supposed to be sent by the controller prior DISC_UNIQUE_BRANCH in order to unmute all muted devices? Should I add it in the port-turning algorithm during Discovery? Same goes for the DISC_MUTE?

And what about Missing Response, what will happen then?

There's no required behavior, either behavior is valid. But, you do need to consider that the device being discovered may be attached to the responder port, not just to the inline device's downstream command ports.

A common mistake is to simply AND together all of the command ports and drive the resulting waveform back to the responder port during the discovery response period. This works if all of your fixtures are on the "outputs" of the splitter, but will create bus conflicts if there are other fixtures on the "input" port.
Is this the reason the device should listen to Responder port too? If it is pulled LOW then the repeater should go to normal data flow (?)

The 5.8ms discovery response period includes time for transmission delays, as well as 200us of extra margin, and is officially only valid at the controller.

For inline devices it can be a bit harder to determine what value to use. You'll want to use a value somewhere between 2.9ms (DUB response delay + Max packet time) and 5.8ms. I think I use 5.6ms in my implementations.
Again, thank you for this. I will keep that in mind when testing the hardware.

Again, either behavior is valid. Personally I prefer to send it to all ports on the device because it allows you to connect a sniffer to any port in the splitter, which can make for easier troubleshooting.
If I go with routing the data from the active to all the ports, I think I need to change a little the concepta as I am trying to build opto-isolated repeater. Maybe I will stick to data sent only to responder for now, just to run and test it. Later I might change it to all ports.

No need to apologize. You're asking good, solid technical questions, which is exactly why this forum exists.
Thank you for the encouraging words, but I am really a RDM noob!

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