An audio system has a base station and a plurality of wireless microphones that are associated with the base station. The wireless microphones operate to capture acoustic audio information and to transmit this audio information to the base station. Each of the wireless microphones operate to detect whether or not they are connected to an external voltage source. If any of the plurality of the wireless microphones determines that they are not connected to an external voltage source, then it is controlled to transition to a first operational state. Or if a wireless microphone determines that it is connected to an external voltage source, and depending upon the voltage level detected, the microphone can transition to either a second or a third operational state.