26 NTT Technical Review 1. Introduction Even with the availability of videoconferencing systems (VCSs), there are still occasions when there is no substitute for direct face-to-face discussions. Conventional VCSs have aimed to create a strong feeling of presence by using high-quality audio and video and virtual reality technology. However, they do not fully recreate the interactions that naturally take place between people who are gathered in the same room. For example, if one person (John) sees another person (Mary) from a diagonal perspective, then Mary should also see John from a diagonal per- spective. The apparent distance of John from Mary should also match the apparent distance of Mary from John. If John moves, then his apparent direction and distance from Mary should correspondingly change, and vice versa. Their positional relationship should also be immediately apparent to a third person who is viewing them from the side. These phenomena that people take for granted when they are all in the same room are not conveyed by conventional VCSs. We have developed an advanced telecommunication sys- tem called the “t-Room” that creates the feeling of being in the same room for users who are actually separated spatially. To overcome the spatial barrier, we use the simple approach of building rooms with an identical layout, including walls of display screens on which users and physical or virtual objects are all shown at life size. In addition to overcoming the spatial barrier, we think it is important to support collaboration among people in different time zones, time senses, and time scales. For example, when people in Europe have a meeting at 10 am with people in the USA, the people in the USA have to stay awake until midnight and dis- cuss serious matters while fighting off sleepiness. Arranging a meeting among busy users is always tough, and often people want to postpone participa- tion in a less important meeting because they give higher priority to more pressing tasks. Commonly used asynchronous media, such as email, mailing Selected Papers Keiji Hirata † , Yasunori Harada, Toshihiro Takada, Shigemi Aoyagi, Yoshinari Shirai, Naomi Yamashita, and Junji Yamato Abstract The t-Room is a remote computer supported cooperative work (CSCW) system that we are develop- ing. Our approach is to build rooms with an identical layout, including walls of display screens on which users and physical or virtual objects are all shown at life size, and to provide symmetry of awareness and immersion in each other’s physical space. This allows users in the t-Rooms to feel as if they were in the same room. Furthermore, by introducing recording and playback capabilities to the activities that occur within the t-Room, we can achieve asynchronous communication that overcomes the temporal barrier. The t-Room has greater potential to reproduce reality and awareness in remote collaboration than con- ventional videoconferencing systems. Moreover, as a step toward the future phone, it will enable us to implement a wide variety of telecommunication services that give the feeling of being in the same room and to create a new social interaction style through a large-scale immersive user interface. The t-Room—Toward the Future Phone † NTT Communication Science Laboratories Soraku-gun, 619-0237 Japan Email: hirata@brl.ntt.co.jp