Well, I've already been told that there will be a serial port compatible with MIDI interfaces a few pages back in this thread (I assume original Amiga MIDI interfaces, I didn't get an answer when I asked that)
The serial port is compatible with Amiga baudrates including the one used by MIDI. Since our board is very small there was no place to put an old-fasion 25-pin serial port connector. We have just put its 9-pin counterpart.
So you cannot connect directly your old MIDI interface, you need to change plugs.
There is another drawback, the 9-pin connector doesn't carry +/-12 Volt power. If your MIDI interface needs it, it should be sourced externally.
When the daughterboard is ready we will think about making a dedicated MIDI interface for our board so your life will be easier.