Plantronics CS50 Base/Headset Swap/Reset procedure.    1. Place headset in the charger base. 2. Hold down the + - volume buttons located on the back of the base until the red light starts flashing. 3. While the headset is still in the charging cradle, hold down the mute switch on the headset until the red light stops flashing. Release the mute switch. (mute switch is the volume button. It pushes in to mute the mic.) 4. Unplug the ac power from the bottom of the headset base and leave unplugged for 10 seconds then plug back into power.