| 摘要 |
A switched integrated wideband and narrowband multiservices digital network (FIGS. 1 and 2) is an ISDM providing universal information services based on wideband and narrowband voice, data, and video communications. It comprises a plurality of service areas (100, 101), each served by a central switching node (110). The central node is connected to a plurality of remote nodes (103) by feeder optical fibers (107) and a control bus extension (106). Network interface equipment (104) at subscribers' (102) premises is connected to remote nodes by distribution optical fibers (105). Each distribution fiber is wavelength-division multiplexed and carries modulated (pulse-analog, pulse-code, or differential pulse-code) wideband digital channels (205) and a multiplexed channel (206) comprising 32 time-division-multiplexed narrowband digital channels (207). One narrowband channel (207D) carries all signaling messages. Feeder fibers are wavelength-division multiplexed and carry modulated wideband digital channels (305), and multiplexed channels (306) each comprising a plurality of time-division-multiplexed distribution multiplexed channels. Each remote node comprises a digital space-division switch (505) for wideband channels, and a digital time-division multiplexer and demultiplexer (506) for multiplexed channels. Each central node comprises a digital space-division switch (606) for wideband channels, and a digital time-division switch (607) for narrowband channels. All switches are controlled by a central node control complex (612) over a control bus (116) and its extensions. Signaling messages are transferred between the signaling-message-carrying narrowband channels and the central node complex by a subscriber signaling subsystem (613) via the narrowband switch and the control bus. A central node optionally includes interfaces (615-618) to other communication systems, and trunk communication fiber (112) and CCIS signaling fiber (117) connections to other central nodes of the network.
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