Description / Abstract: This document defines audio systems characteristics and minimum operational performance standards for aircraft headset microphones, handset microphones (Except carbon), oxygen mask microphones, headsets, handsets, speakers, audio selector panels (ASP) and amplifiers. In addition to postulating operational goals, equipment applications and installations, it recommends test procedures necessary to demonstrate equipment compliance with the stated minimum requirements. This Revision includes requirements covering technology advances, harmonization of DO 214 with other revised standards, addresses industry and FAA feedback for improvements and from advancements in audio, acoustic and communications sciences and methodologies that have developed since the original release of DO-214