A system and method are provided to hold a dialog between communicators while the communicators are viewing their images each other and which prevents the presence of an image display screen from being noticeable in a non-communication state. A first unit for the communicator generates and transmits first data indicating the image of the communicator. A second unit for the communication partner expands the first data received via a communication line to display the image of the communicator on the display screen, and generates and transmits second data indicating the image of the communication partner in front of the display screen. A human sensor is configured to detect that the communication partner is at a predetermined position in a home. Only during the period of the human sensor detecting that the communication partner is at the predetermined position, the display-cum-mirror forms a display screen, and otherwise, a mirror.