A system switches the display screen of an idle web video conferencing device to a digital frame. If there is no video conferencing signal coming into a VoIP phone, its display interface is used as a digital frame. The system includes a display to display the video conferencing image sent by another party over the Internet and outputting a digital frame image when it is idle; a medium processing device including an audio/video (AV) decoder for processing the video conferencing AV signals and an image decoder for processing digital pictures; a switch control device for switching between the AV decoder and the image decoder, achieving the goal of converting between the video conferencing AV and the digital frame image.