You’d better check whether it’s ‘class compliant’ USB MIDI on both devices…
If it is, they should hook up fine.
But a larger issue may loom if you want the DGX to control arranger functions in the Ketron. Yamaha has a nasty habit of doing much of the control functions with sysex, which may be difficult to map to Ketron control codes. Notes, basic controllers like volume, expression etc shouldn’t be a problem, but stuff like Vatiations, intros, fills etc may prove harder to map…
I’m guessing AJ is your goto guy about the nitty gritty. Just be aware, it’s hard to sometimes get a module in as close to the controller keyboard as the buttons and sliders are on an all in one arrangers, so the distance you have to travel to do arranger functions may get far further than you are used to…
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An arranger is just a tool. What matters is what you build with it..!