Grandstream Networks GXV3240D Administration Manual page 70

Handset TX Gain (dB)
Handset RX Gain (dB)
Firmware Version 1.0.1.54

When there is an active call using headset, press HEADSET
button to hang up the call;

When Speaker/Handset is used in dialing/talking status, press
HEADSETbutton to switch to headset. Press it again to hang up
the call, or pressSpeaker/Handset to switch back to previous
mode.
2. Toggle Headset/Speaker

When the phone is in idle, press HEADSET button to switch to
Headsetmode. The idle screen will display a Headset icon. In
this mode, if pressing Speaker button or entering digits, headset
will be used by default;

When there is an incoming call, press Answer icon on the
screen orSpeaker button, headset will be used;

When there is an active call, press HEADSET button to toggle
betweenHeadset and Speaker.
Select the transmission gain of the handset. This is used to handle the
volume setting of handset, it controls the output audio signal. The default
setting is +6dB.
Select the receiving gain of the handset. This is used to handle the
volume setting of handset, it controls the input audio signal. The default
setting is +6dB.
GXV3240D Administration Guide Page 70 of 83