Abstract: An audio input circuit for providing a transducer output signal from a sound transducer to the input of a host device including a universal interface for coupling the transducer output signal to the host device. The universal interface includes a first signal input, a second signal input, a first output conductor, and a second output conductor. Additionally, the audio input circuit includes a switch mechanism coupled between the first and second signal input and between the first and second output conductors for selectively isolating the first output conductor from the second output conductor and for selectively coupling the first output conductor to the second output conductor. The audio input circuit conditions the output of an inexpensive microphone such that the output response of the microphone is ideally suited to the input requirements of the voice recognition host device.