All over the world, and most recently in the United ates, cellular companies have been upgrading their networks, moving from so-called second-generation, or 2G, technology to 3G systems that can deliver vastly more data at faster rates. Throw in the growing number of Wi-Fi connections, and mobile phones, PDAs, and other devices must contend with a tangle of networks speaking different languages at different frequencies. Since most wireless devices can handle only one of these languages and are permanently tuned to particular frequency ranges, they're unable to communicate outside limited geographic areas.
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