This is the schematic of the the auto-crossover 3.5mm TRS MIDI as first used in our WK3 MIDI Thru Eurorack Module

It solves the issue of Type-A or Type-B TRS MIDI Inputs as it works with either polarity.

Feel free to use it but refernce the source in marketing material or any other publications (like manuals) as "LPZW Auto-Crossover MIDI Input", "LPZW TRS MIDI" or "LPZW MIDI In" or similar.

Open-Source Hardware KAY KNOFE OF LPZW.modules