MIDI ports wiring

Good morning,
I am planning to build a small midi device and i was wondering if I did the wiring correctly.
J22 is for input and J16 is for output. Do you see any problems in the pictures?

The connectors are wrong, they should be 5-pin DIN 180° connectors. The numbering of the pins in your image is incorrect. See The MIDI Association - 5 Pin DIN Electrical Specs for the correct pin numbers.

The MIDI input jack should not be connected to ground (except through a small capacitor to ground RF frequencies).
The pins of the MIDI out circuit is also wrong. The data definitely does not go to the center pin. Again, see the link above for the correct wiring.

Depending on the environment this circuit is going to be used in, it may not be a bad idea to include a buffer in your MIDI output.

I cannot understand how to properly wire the PC900V optocoupler. Anyone has any ideas on how to do it?

Did you go through the datasheet? What is it specifically that you're unsure about?

I see 4 pins for the pc900v in the midi document but it has 6. I can't understand wich two pins I should leave empty. I am a noob so I don't really know how to understand what I have to do.

The pins are described at the top of page 2 of the datasheet (“NC” stands for “Not Connected”). You can find a schematic at the top of page 6. If you compare that schematic with the one from midi.org, it should be clear which pin was omitted from the MIDI schematic, and which one you can leave unconnected.

So I think three and six. Am I right?

Yes, you leave (3) unconnected, and connect (6) to 5V.

Ok thank you

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