DualSound is a two-channel (stereo) audio signal generator. You can use it as a versatile signal source e.g. to check out your stereo equipment, to play around with beat frequencies, to check your hearing at high/low frequencies, etc. For each channel (left and right, respectively) you can choose frequency (20Hz to 20kHz), waveform (sine, square, triangle, sawtooth, and white noise), and amplitude (volume). To hear the two generated signals, connect the headphone output of your PocketPC to either a stereo headphone, or a stereo amplifier. (The built-in mono speaker of your PocketPC won't work - unless the frequency on both channels is the same, as both signals are simply added up and that can give strange results.)