See also:

Call volume
Adjusting the incoming or outgoing call volume may improve clarity if reception between callers is unclear. - Incoming calladjusting this setting allows you to hear a difference in volume. - ...

Receiving a call
When you hear a phone ring, the display will change to phone mode. To receive a call, follow one of the procedures listed below. a. Select the “Answer” key on the display. b. Press the phone ...

Temperature
High temperatures accelerate the rate of corrosion to those parts which are not well ventilated. ...