The headset will emit beep tones to indicate status for power, microphone mute, volume and remaining battery charge.
 
Power on One tone (high)
power off Two tones (high to low)
Microphone mute Two tones (high)
Microphone active One tone (high)
Reaching maximum volume Three tones (high)
Reaching minimum volume Three tones (low)
20% battery remaining Two tones (mid)
10% battery remaining Three tones (mid)
5% battery remaining

Five tones (mid, low, mid, low, mid)