The phrase "Concealing Telecommunications Networks" is first introduced as an ultimate philosophical concept in human-to-human or physically evolving "multimedia" communications by employing the same face-to-face mode that is used in natural communications. Then virtual reality (VR) technologies and their current applications are introduced, followed by an introduction of cutting-edge research on "Teleconferencing with Realistic Sensations", which is a communications system that conceals the existence of telecommunications networks. Next, research activities on "vision" and "motion", the most important underlying human functions supporting technologies such as VR, are presented. These activities consist of 1) a perception model that explains how human beings mentally reconstruct 3-D shapes from 2-D information projected on the retina, and 2) research on the close relationship between the senses, i.e., auditory and visual perception, visual information, and muscular motion stimuli. As a practical application, an example of measuring eye movements for early detection of Alzheimer's disease is briefly introduced. Finally, some fundamental problems with stereoscopic 3-D displays on 2-D screens, which can make them more fatiguing than the natural environment, are discussed.

This paper describes digital service integration in the local network. Since the local telephone network accounts for a large portion of the total network cost, it is desirable that a single local network be shared by telephone and nontelephone services. This service integration may include shared local switches, sharedN \times 64kbit/s subscriber lines, and shared wide-band subscriber lines. This paper also describes the total network architecture which can easily adapt to variously changing circumstances in the future.

This concise paper reports the result of a study on a multiplexing scheme for digital data transmission and switching which can handle both anisochronous and isochronous data traffic of various mix, mainly in one digital channel of PCM primary multiplex level (e.g., 1544 kbits/s) and corresponding time-division switch (TDSW) of data-switching equipment. The study aims to determine a unified scheme which is economical and flexible for intercity heavy-traffic data links, to accommodate a wide range of data speeds. The paper describes various multiplexing schemes and analyzes their features in terms of frame structure, synchronization time, error-correction capability, compatibility with signaling, hardware complexity, etc. A bit-interleaved multiplexing scheme is chosen as suitable and is applied in a laboratory model of a digital data switching system, the DDX-1 System.