er loops (subscriber lines). 11. What is the theoretical capacity of a four-digit telephone number? Of a three-digit exchange number? 12. What is the common colloquial name for an NPA code? 13. What is the rationale for having a tandem switch? 14. Define grade of service. What value would we have for an objective grade of service? How can we improve grade of service? Give the downside of this. Give the basic definition of the busy hour. Differentiate simplex, half-duplex, and full duplex. What is double seizure? 19. On what kind of trunk would double seizure occur? What is a full-mesh network? What is a major attribute of a mesh network? What are two major attributes of a star network? Define a traffic relation. On a hierarchical network, what is final route? 24. Give at least three reasons for the trend away from hierarchical routing. 25. List at least six QoS items. List at least one international standardization body, one regional standardization group, and three U.S. standardization organizations. 27. Define a POP and POT. INTRODUCTORY CONCEPTS REFERENCES 1. Webster's Third International Dictionary, G&C Merriam Co., Springfield, MA, 1981. 2. IEEE Standard Dictionary of Electrical and Electronic Terms, 6th ed., IEEE Std 100-1996, IEEE, New York, 1996. 3. Telecommunication Planning, ITT Laboratories of Spain, Madrid 1973. 4. R.L. Freeman, Telecommunication System Engineering, 4th ed., Wiley, New York, 2004. SIGNALS CONVEY INTELLIGENCE 2.1 CHAPTER OBJECTIVE Telecommunication deals with conveying information with electrical signals. This chapter prepares the telecommunication novice with some very basic elements of telecommuni- cations. We are concerned about the transport and delivery of information. The first step introduces the reader to early signaling techniques prior to the middle of the nineteenth century when Samuel Morse opened the first electrical communication circuit in 1843. The next step is to present some of the basic concepts of electricity; this is mandatory for an understanding of how telecommun