Abstract: A display system according to the present invention is provided with a display unit, a display control unit, a touch panel, and a detection unit for detecting contact with respect to the touch panel. In the case of a first operation mode, the display control unit performs predetermined display when there has been contact at the location of a predetermined image on the touch panel. In the case of a second operation mode, the display control unit implements a display system for performing predetermined display when there has been contact on the touch panel, regardless of whether or not the predetermined image is present and regardless of the location of said contact.

Abstract: A color still picture transmission system includes color visible telephones which are coupled to each other through a telephone network. In succession to luminance signal data of all picture elements forming a whole screen, respective averaged values of two kinds of color difference signal data of four picture elements being adjacent to each other are sent from the color visible telephone at a sending party to the color visible telephone at a receiving party through the telephone network, a modem and a network control unit.

Abstract: A system for transmitting image data on a telephone network or equivalent, which typically includes video or visual telephones as apparatus of sending part and receiving part. In the video telephone of sending part, when an image data sending key is operated, a DTMF signal generator included in a modem is started to operated and a specified DTMF signal, for example, DTMF-A signal or DTMF-B signal is sent as a signal DTMF-DTA to a telephone circuit through a network control unit for approximate 300 milliseconds. Succeedingly, in spite of presence or absence of a responsive signal from the video telephone of receiving part, a non-signal state is formed for approximate 75 milliseconds, immediately thereafter, the image data is sent from the video telephone of sending part at a transmission speed of 4,800 bps or 2,400 bps.