MARATHON ALERT TONES
3 Quick Beeps When Turning On = The headset has no link to the base.
3 Quick Beeps When On A Call = The headset is out of range of the base.
3 Quick Beeps When Adjusting Volume = At the top or bottom of the volume setting.
1 Short Beep Every 20 Seconds = Low Battery Warning
1 Short Beep Every 15 Seconds = Headset is muted