Dell (Altec Lansing) A425 Subwoofer Pinouts
This is a standard female DB-9 serial port.
Here are the pinouts.
Pin 1 = Left Speaker Out +
Pin 2 = Left Speaker Out - (Common Ground)
Pin 3 = Left Line In +
Pin 4 = Right Line In +
Pin 5 = Left/Right line In - (Common Ground)
Pin 6 = Right Speaker Out +
Pin 7 = Right Speaker Out - (Common Ground)
Pin 8 = Power A
Pin 9 = Power B
Jumper (short) Power A to B to turn on.
If you want a volume control you need to put one on the inputs. You will buy buy a stereo volume control or potentiometer.
Here is some info on how to do this.http://g4tv.com/screensavers/features/43665/Pump-Up-The-Volume.html