Plantronics 370 manual Headset Controls, Briefly push up or down on the volume button for

Headset Controls

Turn on the headset	Press and hold the call control button until the
	indicator glows blue. You will hear ascending
	tones.
Turn off the headset	Press and hold the call control button until the
	indicator glows red. You will hear descending
	tones. When power is off, indicator stays off.
Answer a call	Briefly press the call control button.
	When you receive a call, your phone may ring
	before your headset rings. Wait until you hear
	the ring in your headset before you press the call
	control button to answer the call.
Reject a call	Press the call control button for 2 seconds.
End a call or cancel	Briefly press the call control button.
an outgoing call
Make a call	Enter number on your phone, press send, and
	the call is automatically transferred to headset; no
	need to press call control button.
Adjust the volume	Briefly push up or down on the volume button for
	incremental volume steps. You will hear two tones
	(high tone followed by low tone) at the volume limit.
	WARNING Do not use headphones/headsets at high
	volumes for an extended period of time. Doing so can
	cause hearing loss. Always listen at moderate levels. See
	www.plantronics.com/healthandsafety for more information
	on headsets and hearing.