ose a handset from among a large selection with different features from many different vendors. 1.5 Standards Organizations Many organizations are involved in standardization work. We look at them from two points of view: (1) the players in the telecommunications business Introduction to Telecommunications Network Engineering involved in standardization and (2) the authorities that approve official standards. 1.5.1 Interested Parties Figure 1.3 shows some groups that are interested in standardization and par- ticipate in standardization work. Let us look at a list of these parties and their most important interests, that is, why they are involved in standardization work. Network operators support standardization for these reasons: To improve the compatibility of telecommunications systems; To be able to provide wide-area or even international services; To be able to purchase equipment from multiple vendors. Equipment manufacturers participate in standardization for these reasons: To get information about future standards for their development activities as early as possible; To support standards that are based on their own technologies; To prevent standardization if it opens their own markets. Service users participate in standardization for these reasons: To support the development of standardized international services; To have access to alternative system vendors (multivendor networks); To improve the compatibility of their future network systems. Equipment manufacturers Network Academic operators experts Service users Figure 1.3 Interested parties. Introduction to Telecommunications Other interested parties include governmental officials who are keen on having national approaches adopted as international standards and academic experts who want to become inventors of new technological approaches. 1.5.2 National Standardization Authorities National standardization authorities approve official national standards. Many international standards include alternatives and options from which a national authority select