The Aerocom III is a 2-place stereo portable intercom with IntelliVox™, a completely automatic VOX squelch. Each microphone computes the difference between speech and cabin noise. It opens instantly when somebody talks and only the microphone spoken into is active.This prevents un- wanted background noise from entering the audio system. Powered by a 9V battery (10 hrs. of use) or aircraft power. Features low battery alert. By using external push-to-talk buttons (not included), both the pilot and copilot positions have the ability to transmit over the aircraft radio. The Aero- com III will route stereo music to the headsets through the optional music cable.The music automatically mutes when there is intercom activity or radio traffic.There are two modes controlled by a top-mounted switch. In "ALL" mode, both positions hear radio communications, music, and have inter- com capability. In the ISO mode, only the pilot side is connected to the aircraft radios, with- out intercom or music distractions.The copilot position continues to have music, and inter- com communications with an expansion unit if installed. The aerocom III is expandable to 4-places with the Aerocom EX expansion unit available by special order. This contains separate music input and dedicated IntelliVox™ processors.