Plantronics Calisto 400 User Guide - Calisto P420-M USB - Page 8

3 Using your P420-M USB speakerphone Volume up, volume down and mute 1 Press the down arrow (left button) to decrease the speaker volume. 2 Press the up arrow (right button) to increase the speaker volume. Note A prolonged press of the volume buttons will increase or decrease the volume several levels until you stop pressing the button. The P420-M will beep when a volume up button or volume down button is pressed and a series of beeps when a prolonged press is performed. Each beep signals one level of volume increase or decrease. 3 Press the microphone icon (middle button) to mute the microphone. A blue light will flash indicating that the microphone is muted. 4 Press this button again to unmute. The blue light will become solid indicating the microphone is unmuted. Plantronics P420-M USB Speakerphone 8