Midi Standards

Traditionally midi had 16 channels. Because they are in binary and since computers count from zero they are sometimes numbered 0-15.

USB & MIDI: Everything you need to know to get it right (USB MIDI Host vs Interface explained)

5 Pin Midi 
5 Pin Midi is the traditional Large midi.

3.5mm TRS jack midi 
Is a newer standard. Before it was standardized equipment manufacturers used two incompatible standardsTRS-A and TRS-B. Eventually TRS-A was standardized on. Which should help with future equipment.

• https://midi.org/specification-for-use-of-trs-connectors-with-midi-devices
• https://www.theatreofnoise.com/2017/08/midi-wiring-diagrams.html

USB Midi

Ableton Link

• https://www.ableton.com/en/link/
• https://ableton.github.io/link/
• https://github.com/Ableton/link