This device is inserted between the Mercury host device (such as a Mercury Interface Unit Audio Expansion Board port) and a hardware panel to reduce engine and background noise at the audio source by up to 12dB. It is typically used for applications where an operator is communicating with remote users in high ambient noise environments, like drive through lanes. The device uses Adaptive Speech Filter technology. A patented algorithm is designed to filter noise from microphone signals containing both speech and noise. This unit is effective against a wide variety of broadband “stationary” noises whose amplitude and pitch change slowly compared to the spectral variations characteristic of human speech. As the background “stationary” noise changes, the ASF adapts to the changes (1-2 second delay) and continues to filter out the noise.