kustom:
Yes, that's what I wanted! Thanks. Still wondering about RX/TX pins. I guess they just connect directly, after all it's microcontroller-to-microcontroller communication.
A MIDI device needs one cable in each direction (in / out).
It also uses optocouplers on the inputs, which is what you need to drive with the Arduino's serial output. ie. It's not just TTL logic, it's more like lighting up a LED with the output pin.
You need to read the MIDI specs before connecting anything.