We have just introduced our new MIDI adapter for the Prototyping System for Teensy 4.1. The adapter provides the physical and electrical interface between the Teensy 4.1 and external MIDI devices that use the standard 5-pin MIDI DIN connectors.
This adapter adds an opto-isolated MIDI input connection. The opto-isolated input electrically protects the Teensy 4.1 in the case where the input may be shorted or misconnected.
A buffered output similarly serves to protect the Teensy 4.1 from the sometimes unfriendly outside world.
The adapter is a half-size board that is designed to be mounted on the right side of the adapter area so that it can be used in conjunction with the Teensy Audio Adapter. Standoffs are provided to help support the left side of the board.
Some MIDI devices now use MIDI over USB for connections and the Prototyping System for Teensy 4.1 has a USB Host port built-in which can be used for making those connections.
MIDI Adapter in use with a MIDI keyboard
Find more info on the adapter at https://protosupplies.com/product/midi-adapter/