The BAA01 Bluetooth® Audio Accessory is a panel-mount unit designed to add Bluetooth connectivity to existing avionics, audio, PA, or loudspeaker systems.
The BAA01 can support discrete call and music audio using the built-in Bluetooth audio profiles. An integrated front-panel LED annunciator displays the power, pairing, and link status. Adjust control and volume of the Bluetooth audio playback using the BAA01’s built-in front panel rotary encoder.
The BAA01 provides rear connected external inputs which can be used to control the Bluetooth audio remotely through externally mounted switches.
https://www.aem-corp.com/audio/bluetooth-audio-accessory