1. FIGURE 12-1 Interconnection of switching exchanges in North America. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

2. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

3. FIGURE 12-2 Long-distance switching hierarchy within the PSTN depicting possible routes to complete a call between parties A and B. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

4. FIGURE 12-3 Long-haul network depicting various trunk media. (Courtesy of Bell Laboratories.) Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

5. FIGURE 12-4 Switching centers throughout the United States (Courtesy of Bell Laboratories.) Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

6. FIGURE 12-5 Four-wire trunk circuit with separate amplifiers for each direction. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

7. FIGURE 12-6 Hybrid two- and four-wire terminating circuit. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

8. FIGURE 12-7 Echo suppressor. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

9. 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. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

10. FIGURE 12-9 (a) m-Law used for companding in the United Sates. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

11. FIGURE 12-9 (b) A-law used for companding in Europe. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

12. 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. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

13. FIGURE 12-17 Simplified SXS call procedure to subscriber 5831. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

14. FIGURE 12-19 Detailed views of the crossbar switch: (a) principle of operation; (b) finger action. (Courtesy of Northern Telecom.) Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

15. FIGURE 12-20 Crossbar switch with 25% blocking Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

16. 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

17. 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. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

18. FIGURE 12-26 Hierarchy of the Bell System FDM groups. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

19. FIGURE 12-27 (a) Formation of the Bell System’s channel group; (b) frequency distribution of the channel group. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

20. FIGURE 12-28 Frequency distribution of the Bell System supergroup. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

21. FIGURE 12-29 Simplified diagram illustrating TDM. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

22. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

23. FIGURE 12-30 Block diagram of the North American digital multiplexing hierarchy. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

24. FIGURE 12-32 T1 carrier frame format. Warren Hioki Telecommunications, Fourth Edition Copyright ©2001 by Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.