Application Monitoring, control E-mail, Web access, Cable replacement some video Memory Requirements 4-32 KB 256 KB Battery Life (days) 100-1,000 0.5-5 Network Nodes Unlimited Bandwidth (Kbps) 20-250 11-54 Range (meters) 1-100 1-100 factor orthogonal frequency and code-division multiplexing (VSF- OFCDM) is one of these. Currently being studied by DoCoMo in Japan, VSF-OFCDM can theoretically transmit at speeds as fast as 100 Mbps outside and as fast as 1 Gbps indoors. As a test bed, DoCoMo has built a mobile IP data network to stress the technology, and early results are quite favorable. And while this technology is nowhere near ready for prime time, it bears watching. The Mobile Appliance The mobile appliance concept is enjoying a significant amount of atten- tion of late because it promises to herald in a whole new way of using network and computer resources-if it works as promised. The problem with so many of these new technologies is that they overpromise and underdeliver-precisely the opposite of what they're supposed to do for a successful rollout. 3G, for example, has been billed as "the wireless Internet." Largely as a result of that billing it has failed. It is not the Internet-far from it. The bandwidth isn't there, nor is a device that can even begin to offer the kind of image quality that Internet users have become accustomed to. Furthermore, the number of screens that a user must go through to reach a desired site (I have heard estimates as high Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Access Technologies Access Technologies as 22!) is far too high. Therefore, until the user interface, content, and bandwidth challenges are met and satisfied, the technology will remain exactly that-a technology. There is no application yet, and that's what people are willing to pay money for. Chapter Summary Access technologies-used to conn