II-2. MIDI Electrical Standard
A MIDI in interface uses an
opto-isolated current loop.
5 Volts flows through a
total of 660 Ohms (min.)
of resistance. There is
a protection diode in
case someone wires up
somethingbackward. MIDI
out is just a buffer and
some resistors. MIDI thru is
a buffered pass-through of
the MIDI in signal.
More Information on Building MIDI Interfaces