FIGURE 12-1 Interconnection of switching exchanges in North America. Warren Hioki...

FIGURE 12-1 Interconnection of switching exchanges in North America.

Warren HiokiTelecommunications, Fourth Edition

Copyright ©2001 by Prentice-Hall, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

FIGURE 12-2 Long-distance switching hierarchy within the PSTN depicting possible routes to complete a call between parties A and B.




FIGURE 12-3 Long-haul network depicting various trunk media. (Courtesy of Bell Laboratories.)




FIGURE 12-4 Switching centers throughout the United States (Courtesy of Bell Laboratories.)




FIGURE 12-5 Four-wire trunk circuit with separate amplifiers for each direction.




FIGURE 12-6 Hybrid two- and four-wire terminating circuit.




FIGURE 12-7 Echo suppressor.




FIGURE 12-8 Comparison between a transmission system with and without companding. The diagram depicts signal strength versus transmission distance: (a) transmission system without companding; (b) transmission system with companding.




FIGURE 12-9 (a) m-Law used for companding in the United Sates.




FIGURE 12-9 (b) A-law used for companding in Europe.




FIGURE 12-14 Three satellites in geosynchronous orbit spaced 120° apart can provide full coverage of the Earth, with the exception of the polar caps.




FIGURE 12-17 Simplified SXS call procedure to subscriber 5831.




FIGURE 12-19 Detailed views of the crossbar switch: (a) principle of operation; (b) finger action. (Courtesy of Northern Telecom.)




FIGURE 12-20 Crossbar switch with 25% blocking




5 ESS Features

• Modular design– Provide service from rural to large

metropoplitan areas

• Runs on C code and UNIX operating system

• Wide range of custom features– see Pgs 318-319 of textbook

FIGURE 12-25 (a) Three independent sine waves mixed with subcarrier frequencies to produce the FDM output; (b) frequency spectrum of the FDM output signal.




FIGURE 12-26 Hierarchy of the Bell System FDM groups.




FIGURE 12-27 (a) Formation of the Bell System’s channel group; (b) frequency distribution of the channel group.




FIGURE 12-28 Frequency distribution of the Bell System supergroup.




FIGURE 12-29 Simplified diagram illustrating TDM.




FIGURE 12-30 Block diagram of the North American digital multiplexing hierarchy.




FIGURE 12-32 T1 carrier frame format.




FIGURE 12-1 Interconnection of switching exchanges in North America. Warren Hioki...

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