Question: How can I use an external display to view the GXV3140 screen?
Answer:

You can use a TV for the display of the GXV3140 by connecting the audio and video jacks on the right side of the GXV3140 to your external display. Select the aspect ratio of your TV and press the submit button. The display will be switched over to the TV.

Note: TV out is disabled in the default factory settings. If TV out is configured, the LCD display will be switched to the external display and nothing will be displayed on the GXV3140’s LCD screen. Therefore, if you have configured TV out and wish to switch back to the LCD screen, you should reboot the phone or login to the web configuration interface and disable TV out.