Discovery 640/645: How to Power On
How do I turn the Discovery 640/645 headset on and off?
Turn on the headset by pressing and holding the call control button until the headset indicator light glows blue. You will hear a beep in the headset when it turns on. The indicator light will flash blue every 6 seconds while on. To turn it off, press the call control in for 6-8 seconds. The indicator light will glow red while powering down, and there will be a beep in the headset. No lights will show when the unit is off (unless it is charging).