Firmware Version 1.0.1.27 - Grandstream Networks GXV3240 Administration Manual

Firmware Version 1.0.1.27

Headset mode. 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 or Speaker button, headset will be used;

When there is an active call, press HEADSET button to toggle
between Headset and Speaker.
GXV3240 Administration Guide Page 63 of 76