Comments: MIDI Tutorial
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In the cute drawings of the MIDI connectors, I believe that the MIDI In side should also have a series 200 ohm resistor.
I know this is an older article but I've been using it as a reference as I work on my first little MIDI project - and one thing I noticed: the schematics you provided - the pin numbers on the Opto isolator appear to be wrong - - or at least a bit confusing - I suppose they may match some specific model but since none was listed I looked and saw a lot of folks using 6n138 - the diagram you have shows the leads and their connections to the chip and if you follow the diagram and ignore the numbers it's good, but the way the numbering appears in your circuit confused me quite a bit
It would appear that you have a 1 on what should be pin 2 and a 2 on what should be 3, a 6 on what should be 8 and a 4 on what should be 6
Basically the drawing looks right but the numbers that seem to be assigned to the Opto-isolator pins are wrong I looked up several diagrams for the 6n138 to be sure - if you were referring to a different Opto-isolator and those pin outs are right for it I'd love to know which model you chose / used for the sake of completeness
I've really appreciated this tutorial though as it has helped me get a good solid basis for the technical side (I've used MIDI for years as a musician but never really got into the hardware layer)