The intelligent choice..... After a decade there is finally another portable intercom good enough to bear the PS Engineering name. The Aerocom III is the only portable intercom with IntelliVox®, a completely automatic VOX squelch. The same intercom VOX squelch used in the top-of-the line PMA7000MS audio panel. Clear cockpit communications is as easy as a casual conversation with the Aerocom III. No more fiddling with knobs. No more clipped words. You don't need to reach for the intercom as you change power settings because the squelch processor is constantly monitoring each microphone, and adjusting the threshold for the ambient noise.No more headset swapping and matching. Each microphone is handled independently, therefore, any combination of aviation headsets will work with the Aerocom III. A 9-volt battery or aircraft power can power this 2-place intercom. A single 9-volt battery provides 10 hours of use. When the battery is nearing the end of its life, a gentle beep in the headset will remind the user that it is time for a change. IntelliVox®, is what makes the Aerocom III so remarkable. By harnessing the power of microprocessor electronics, each microphone can compute the difference between speech and cabin noise. It opens instantly when somebody talks. Each microphone has its own processor circuits so only the microphone spoken into is active. This prevents unwanted background noise from entering the audio system. By using external push-to-talk buttons (not included), both the pilot and copilot positions have the ability to transmit over the aircraft radio. Only the person pushing their push to talk button will be heard. The Aerocom 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.The Aerocom III is expandable to 4-place with the Aerocom EX expansion unit. This contains separate music input, it's own IntelliVox® , processors and independent volume control. There are two modes controlled by a top-mounted switch. In "ALL" mode, both positions hear radio communications, music and have intercom capability. In the "ISO" mode, only the pilot side is connected to the aircraft radio, without intercom or music distractions. The copilot position continues to have music and intercom communications with an Aerocom EX, if installed.