SCREEN-BASED MULTIMEDIA TELEPHONY

Today, telephone users are already realizing the multimedia dream as t he AT&T VideoPhone 2500, Picasso(R), and Vistium(TM) products are intr oduced into consumer's homes and onto office desktops. A major, common element of these products is a display screen that provides a visual perspective. In addition, end-users now have a choice about what they can view at any given instant. The quality of this choice depends on t he product itself, the feature set being used, and the bit rate of the telephone transmission medium. This bit rate varies from the very low speeds of the public switched telephone network (PSTN) to the higher speeds of basic-rate ISDN and ultimately to the very high speeds of br oadband and asynchronous transfer mode technologies. This paper discus ses these factors, the overall architecture of the three AT&T products ,, as well as their rich sets of features. In addition, key markets an d applications are highlighted.