The introduction of optical fibers in local area networks makes it possible to implement wide-band communication systems integrating all the communication services (telephone, data, images, etc.) foreseen in future office scenarios. This paper describes a reconfigurable high-speed local communication system, which is currently under development at the Centro Studi e Laboratori Telecomunicazioni (CSELT), conceived to attain high reliability and efficiency features, therefore suitable for a wide range of application environments, such as automated offices, integrated manufacturing, hospitals, etc. The access organization is based on a hybrid (i.e., circuit and packet) protocol, which guarantees each type of traffic the required grade of service, while allowing an optimal exploitation of the transmission capacity. Fault-tolerance issues are taken as a guideline in the overall system conception and, in particular, in the transmission subsystem design. The transmission subsystem presently uses available optical technology to implement a loop-shaped bus topology capable of reconfiguring by means of a distributed algorithms, when a link or node fails.

An experiment of wide-band switched interactive services (video services) is presented. The experiment, named WISE (Wide-Band Interactive Services Experiment) is limited to a small number of subscribers but is representative of a future domestic environment. After a brief presentation of the scope of the activity, the video services that have been implemented, both unidirectional and bidirectional, are described. The system organization, based on a wide-band switching matrix and on the transmission of video signals on a single optical fiber by wavelength-division multiplexing, is then discussed, and the solutions adopted for the transmission equipment are examined. The structure of the service center is afterwards described, together with the subscriber procedures required to access the different services. Finally, some improvements and future possible developments of wide-band interactire systems are briefly highlighted.