Hmmmm, I just noticed - my Core doesn't send ANY SysEx at all. Not even with the test_tx program. It used to give me some SysEx with that, and the SID_V2 still works, too! ??? What 's up with that? MidiOx is configured correctly though (tested with my Roland Synth) and the MidiOut on the Core is hooked up correctly, too... Strange. Any idea, TK? /edit: Some add. info