    Connectors: D25 male
    Resistors: 640k,320k,160k,80k,40k,20k,10k,5k,390  (+-1%)
               (You can use different values of resistors, but
               the ratio of the values of the resistors must be
               same. 0.5, 1, 2, 4, 8, 16, 32, 64 etc.)
                     1, 2, 4, 8, 16, 32, 64, 128
    Capacitor: Electrolytic or solid Tantalum 10 uF 10V

                SCHEMATIC

        +---+
        | 2 | ---<640k>---+
        | 3 | ---<320k>---+
        | 4 | ---<160k>---+
        | 5 | ---<80k>----+
        | 6 | ---<40k>----+
        | 7 | ---<20k>----+-----+---- 10 uF -------> Out
        | 8 | ---<10k>----+     |
        | 9 | ---<5k>-----+   <390>
        |   |                   |
        | 25| ------------------+------------------+ 
        +---+                                      |
                                                  ===
                                                 Ground 
                How to build

Solder all D25 male connector pins to corresponding D25 female connector pins 
(pin 1 to pin 1 etc) Connect the resistors according the chematic. It is maybe 
not possible to obtain exact resistor values. If you can't obtain them, try 
nearest values. <1% deviation is acceptable.

        How to use

Connect this circuit to the centronics printer port of your IBM PC or 
compatible. Connect the printer cable to the D25 female connector of the 
circuit. Your printer should work correctly with this circuit and you can keed 
this circuit connected all the time. Connect the sound output to your stereo 
system. Line in and mic lines are suitable because the output level of this 
circuit is adjustable (about 0-2V PP). The sound quality is very good.
