Experiences gained with the installation and operation of an experimental communication system are reported. The system uses distributed switching in its narrow-band part, integrating ISDN services and high-speed data communication, and a star coupler as a central device. LiNbO/sub 3/ optical switches behind the star coupler prevent line tapping. In the wideband subsystem, optical routing is used for videophone. The central device is a space-division-switching unit consisting of cascaded 4*4 LiNbO/sub 3/ switching matrices. Both the narrowband and wideband parts of the system have been operated with bit error rates less than 10/sup -9/.>

Subscriber stations in service integrated communications systems can be implemented in many different ways. Within the HHI Broad-Band Communications System two extremely different solutions have been realized: on the one hand, subscriber stations in a conventional star type network with central exchange and analog transmission, and on the other hand, subscriber stations in a digital, loop-structured network employing distributed control. In both cases, the same services (telephone, data, videophone, TV, and stereo broadcasting) are carried to the subscriber via one single optical fiber. This paper describes these different realizations of service integrated subscriber stations in detail. The size of terminal equipment, power consumption, extendability to further subscribers, and services and reliability are the main parameters of an appropriate comparison. An analysis of both realizations, giving emphasis to the switching and multiplexing, and the feasibility of analog optical transmission will be made. Alternative realizations and an estimation concerning subscriber stations for future service integrated broad band communications systems will be presented.