Simple MIDI interface for the Soundblaster series of sound cards
================================================================


15 pin D connector             220R

1 +5v ------------------------/\/\/\---------------\
                                                    \ 4
5 gnd ---------------------------------------------2      MIDI OUT
                                                    / 5
12 tx ------------------------/\/\/\---------------/
                                220R


1 +5v -------+------+
             |      |
             \      |
        220R /      |
         R1  \      |
             /      |
             |      |                  220R
15 rx -------+      |        +------+-/\/\/\--------\
             |C     |B       |A     |                \  4
           +-+------+--------+-+    |                       MIDI IN
           |  6      8       2 |  -----              /  5 
           |                   |   / \ IN914      +-/
           |      PC900        |   ---            |
           |                   |    |             |
           |  5              3 |    |             |
           +-+---------------+-+    |             |
             |E              |K     |             |
             |               |      |             |
5 gnd -------+               +------+-------------+


[PC900 is a high speed optoisolator]