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  • I've had a go at this today, I have been experimenting with your explanation of the circuit...

    So this is the result...

    The white crocodile clip is the decoded DMX data from the shield. Through a 1n4001 diode into a 1uF capacitor, and a 1KΩ resistor to ground.

    This is the result on the scope...

    D0: Data– going into DMX Shield.
    D1: Data+ going into the DMX Shield.
    D2: Is the Logic analysers reading of the interrupt output.
    1: Is the same as D2 but on the scope. You can see the signal drops to close to 1V but only after the entire packet.

    The particular DMX board I am using is a Chauvet Obey 6 which appears to be controlling 6 faders on 6 pages/fixtures... i.e. 36 channels only at the moment.

    I am going to play about with the values now but I am not sure what I am really doing. I think probably a smaller capacitor as the drop off is long... maybe 0.1uF.

    If you see this and have a bright idea I am going to be at my desk for an hour or two with the setup to see if I can get below 1V at the start of the data. However I am not sure what the start is...

    The signal goes low for a long period, then high, and low again for a short period (is there a channel 0?) then the bits can clearly be seen with a short break between each...

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