Hey everyone. I hope this is an okay place to ask this. What you see up above is a schematic for two MIDI inputs, one using a PC-900 optoisolator, the other using a 6N138. The one on top is from a schematic I'm reimplementing, and the bottom is from my MIDIbox SID-NUXX. I believe that the two should be functionally equivilent, with each holding the MIDI IN line at +5V, and then MIDI data causing brief pulses before it returns back to 5V. (This is also what was observed on the scope.) Just so I