. We have very few signatures belonging to William Shakespeare, but we know he spelled his name three different ways. Worse, we are not sure what he wanted Hamlet to say at certain key moments. Was Hamlet talking about "this too, too solid flesh," as most scholars think, or was it sullied flesh or perhaps sallied (attacked) flesh? If Ben Johnson's dictionary had come out before Hamlet, we might be certain. But reading Shakespeare might be a lot less fun, too. When we want to lay out instructions for how things should be done, we create a standard. Standards are rules, and people have odd reactions to rules. People who want to make sure that things work tend to like standards. People who like to have fun, do things their own way, or do things the best way they can do not like standards. The world of wireless engineers contains a lot of people with each of these attitudes. In practice, however, standards are essential for radio and telephony. The reason for this is that standards specify what the two components on either side of an interface must do to communicate with one another. In defining what each component will send, we define what each component must be able to receive. If we then define the states of each component, the other relevant inputs, and the appropriate response of each com- ponent, we have defined how each device operates to fulfill its role in the system. 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. General Cellular Standards Standards for Cellular Systems 9.1.1 Types of standards Standards are not laws. It is possible to develop systems without standards or with purely proprietary standards and succeed in business. One of the world's most ubiqui- tous and successful cases of standardization, the system of red, yellow, and green traf- fic lights, was never set as a standard. It was deployed, it worked, and it was accepte