A:Answer The Key Changer feature for the LG 220W Hi-Fi Entertainment System with Bluetooth® Connectivity, Model # OM4560 is explained on page 28 of your owner's manual. It is only available in CD, USB or Bluetooth functions and if a microphone is connected "NOT SUPPORT" will appear on the display to indicate that the feature has been deactivated. To initialize it, you will need to change the function, disconnect the microphone or change the music. The function may also not be initialized depending on the status of connected devices...^IFV