 the Internet, an increasing share of fixed telephone communications will be transferred to the Internet. Also in the core network of PSTN, use of Internet technology will increase. 7.3 Wireless Communications As just mentioned, telephone service is moving from wired networks to wire- less cellular networks. The second generation cellular systems provide text Future Developments in Telecommunications messaging service, which became much more popular than initially expected. Cellular networks have been further developed to provide better and better data and information services. The success of information services is very dif- ficult to estimate. Businesses may explore them only if attractive applications are published. Implemented packet-switched technology will allow low-cost use of those services. Location-based services, in which the information pro- vided depends on the user's current location, can provide many business opportunities. Cellular networks will also be used for wide-area Internet access. The packet-switched air interface makes it possible for network operators to pro- vide high-data-rate communications at attractive fees. For better perform- ance WLAN technologies will be integrated with cellular systems. For high-data-rate short-haul data communications, WLAN technologies will be available for travelers. Personal area network technologies, as a less complex option to WLAN, will make our living easier by connecting electronic devices to each other in homes and offices. There will be new applications that we have not yet thought of today. 7.4 Optical Technology Development of optical technology took a major step in the 1990s when DWDM technology and optical amplifiers began to be used. Chapter 4 pro- vided an introduction to these technologies. DWDM offers a very economi- cal way to increase the transmission capacity of the core network where optical cables are available. In the future, the optical core network will become more cost effective and flexible with the help of optical network ele- ment