Tutorial on MIDI connections, cables and adapters. If your MIDI connection does not work, check this

Couple of decades ago MIDI connections were quite simple. There were those DIN MIDI connectors and cables. Then they started to revise the standard, but it took years and years to get agreement on MIDI 2.0, and meanwhile many manufacturers implemented different solutions.
Thus there is now a wild variety of different MIDI connections, which often confuses people. Many do not seem to know, that there are two different types of 3.5mm TRS MIDI connectors, namely type A and type B. Connectors look exactly the same, it is their wiring that is different.
I made this video to show most common and some exotic MIDI connectors, and how you can solve situations where you have to connect an instrument with type A TRS connector to another instrument with type B TRS connector. Likewise there are still lots of gear with that old and reliable 5-pin DIN connector. I also show how to connect from TRS to DIN, and what you need for that.
This should help to understand common problems with MIDI connections. However there are many special cases which I cannot cover here. Likewise, I cannot give a comprehensive list of what TSR MIDI types every instrument may have. I suggest to check the documentation of your gear.