d. However, given the cost of developing new technology, certification of a standard-and certification of a particular equipment model as meeting that standard-has a tremen- dous amount of power in the marketplace. For practical purposes, we can put standards into six different categories. Here they are, with the most official ones first: International standards are approved by an official body recognized by multiple govern- ments and many companies. For the cellular industry, the most important international standards organization is the International Telecommunications Union (ITU). National standards are approved by a quasi-governmental body such as the American Na- tional Standards Institute (ANSI) in the United States. Adherence to these standards also may be regulated by an official government body, such as the U.S. Federal Communica- tions Commission (FCC). Industry standards are managed by industry groups, such as the Institute of Electrical and Electronics Engineers (IEEE). These bodies often develop standards and propose them to the more official standards organizations. Some industry groups are more tech- nical, developing standards to solve problems, and others are more political or more business-oriented, promoting particular technologies as they develop standards for them. Proprietary standards are developed and maintained by a company who may license use of the standard to other companies SO that they can develop compatible systems. Open standards arise when an organization makes its proprietary standard available for general use at no charge. UNIX is an open standard. De facto standards are accepted ways of doing things that are prevalent in society. The color of traffic lights that we discussed earlier is an example. Of course, a single standard may operate at many of these levels and is likely to change status over time. For code division multiple access (CDMA), many of the stan- dards were proposed by Qualcomm, which holds patents on many chip designs that implement CDMA standards. However, Qual