serial I/O port

                 +---------------------------------+
     ____________|___________                      |
    /2   4   6   8   10   12 \                     |     4 - MASA
  /1   3 | 5   7   9    11   13\                   |     5 - Data output
 --------|-|---------------------                  |     8 - Motor control
         | |                           __   __     |
         | +------------------------<-|  |_|  |->-[ ]    pins 0 & 1 
         |                        0 +-|       |-   |     should be  
         |                        1 +-|       |-   |     connected.
         |                +-----------|       |-   |
         |                |          -|       |-   |
         |                |          -|       |-   |
         +----------------------[ ]-<-|_______|-   |
                          |      |     74LS04      |
                        +---+    |               +---+
                        |   |    |               |   |
                    220 |   |    |               |   | 220
                        |   |    |               |   |
                        +---+    |               +---+
                          |      |                 |
                          |      |                 +--------------------+
                          |      |                          DIN         |
                          |      |                  [3]          [1]    |
                          +----------------------------[5]    [4]-------+
                                 |                         [2]
                                 |                          |
                                 +--------------------------+

 MIDI OUT
 To make such a connection you need : 74LS04 chip
 two 220 ohm resistors, DIN connector...
 Whole interface you can install inside computer, or disk
 drive, after connected to serial I/O output.