, terminal equipment, and network architecture are continually being enhanced to meet and adapt to changing market needs. The detailed product roadmap extends five years into the future and includes a number of important hardware and software devel- opment projects that will result in improved performance, decreased investment, and cost-efficient operations for Mobitex operators. Mobitex is also being used in combination with GPRS, WLAN (802.11), satellite, and CDMA, and we are seeing Chapter 14 Wireless WANs new products such as dual-mode modems, gateway products, and software that support this development. There are also several new Bluetooth-enabled products and applications for Mobitex. 2G: Digital Cellular Radio The growing demand for mobile communications in the late 1980s was well beyond what the analog cellular infrastructure could support, SO digital cellular radio was introduced to increase capacity. The basic cell in analog can handle about 60 subscribers, but in the past several years, the number of people using wireless or mobile services has grown exponentially. Digitalization is an important part of using the existing spectrum more efficiently. Another reason to switch to digital was to improve security. The industry was suffering from a tremendous amount of toll fraud. Creative thieves would stand on busy street corners, intercepting elec- tronic identification numbers and phone numbers and then cloning chips; the next month, you'd have a bill for US$3,000 to an area you'd never called in your life. Digitizing that ID information meant that we could encrypt it to improve the secu- rity. Finally, the digital cellular infrastructure is very closely associated with intelli- gent networks, and that is what gives you the roaming ability to engage conversations when you are outside the area of your own service provider. The digital cellular architecture is very similar to the analog architecture. As you can see in Figure 14.4, a base transceiver station services each cell. But because there are more cel