t of all these protocols is to give a designer the ability to cre- ate a network that will transport the customer's voice, data, video, images, or MP3 files with whatever level of service quality the traffic demands. We now know that data communications protocols make it pos- sible to transport all types of traffic with guaranteed service. Let's turn our attention now to the network itself. In the chapters that follow we will discuss the history of the most remarkable technological achieve- ment on earth-the telephone network. Later we will discuss the anatomy of a typical data network and the technologies found there. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Protocols Chapter 2 Chapter 2 Questions Why are ASCII and EBCDIC important? Are there other character codes that are still in use? What are they? Convert the number 2,387 10 to its base two equivalent. Convert 11010011010102 to its base ten equivalent. Give three examples of noise in a telephone network. Explain the difference between noise and distortion. The OSI Model is referred to as a layered protocol model. Why are layered models advantageous? Explain the difference between layers six and seven. Are they both necessary? Why? What is the difference between connectivity and interoperability? Is one more important than the other? Why or why not? What layer of OSI cares most about each of the following: bits, messages, cells, frames, and packets? Explain the difference between a connection-oriented and a connectionless network, including appropriate applications for each. What is the simplest form of error correction? Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. CHAPTER Telephony Telephony Chapter 3 In 