ogether and make them part of a unified delivery strategy. The name of the game is service, and IP provides the bridge that allows service providers to jump from a technology-centric focus to a renewed focus on the services that customers care about. Chapter Summary A few years ago, while filming a video about telephony on location Texas, I interviewed a small town sheriff about his use of telecommuni- cations technology in his job. I wanted to know how it has changed the way he does his job. "Well sir," he began, puffing out his chest and stick- ing his thumbs into his waistband, "We use telecommunications all the time. We use our radios and cell phones in the cars, and our telephones there to talk here in town and for long distance. And now," he said, pat- ting a fax machine on his desk, "we've got backup." I wasn't sure what he meant by that, SO I asked. "We've always had trouble with the phones goin' out around here, and that was a bad thing. Can't very well do our job if we can't talk. But now we've got this here fax machine." I was puz- zled-I was missing his point, SO I probed a little deeper. "Don't you get it, son? Before, if we lost the phones, we were like fish outta water. Now, I know that if the phones go down, I can always send a fax." Unfortunately, many peoples' understanding of the inner workings of the telephone network is at about the same level as the understanding of the sheriff (who was a wonderful guy, by the way. I set him straight on his understanding of the telephone network and he treated me to the best chicken fried steak I have ever eaten). Hopefully this chapter, and those that follow, are helping to lift the haze a bit. 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. Telephony Chapter 3 We will return to the central office several times as we examine the data transport side of telecommunications, but for now, l