Cover Image

PAPERBACK
$118.00



View/Hide Left Panel

Page 398

supporting aggregate traffic from a single large business location. The ''last mile" that delivers information to or from individual locations has some dominant technologies today. These are twisted pair copper typically supporting symmetrical, two-way, narrow bandwidth (less than 56 kilobits per second) analog transport or, less commonly, medium bandwidth (56 kilobits per second to 1.5 megabits per second) digital transport; and coaxial cable, typically supporting broad bandwidth (the equivalent of 1.5 megabits per second or higher) analog transport—mostly one-way, with two-way expansion widely planned.

Intelligent Features

Intelligent features constitute a broad category, and one that tends to get less than the attention it deserves in many discussions of the next generation infrastructure. A classic example of such a feature in voice (and some circuit-switched data) networks is 800 number service (and the myriad related services that have emerged in the past decade that involve database or routing-table lookup and translation in the network). The tremendous utility of such services is demonstrated by the degree of their widespread use today, mostly for voice services. In the case of data and multimedia networks such a concept again applies, albeit with different implementation details. Directory services, database services, and network-based security services are examples of intelligent service capabilities that vastly enhance the value of the underlying connectivity to users. Currently these features are offered in rudimentary form as part of data and multimedia services, often to a limited base of users. As described below, efforts by AT&T and other industry players are slated to substantially increase the deployment and use of these features beginning this year, expanding rapidly over the next several years to offer more robust and useful sets of features supporting a broader user base.

Messaging

Messaging, involving the storage, processing, and forwarding of information, is becoming widespread and accepted as a mode of information exchange. Voice messaging using premises-based equipment such as answering machines or computer-based voice mail systems is common now. Network-based voice messaging services are available in some areas but are less widely used; their features, functionality, and price structure need to evolve further to provide full-fledged competition to premises-based systems. Data messaging, or e-mail, is now widely used in corporations and is used by the more technically oriented consumers. Substantial progress needs to be made to provide simplified user interfaces, build user awareness, and provide user training, before e-mail can become a commonly accepted form of information exchange for a broad cross section of society. Text-to-speech conversion and vice versa are being actively worked on in research laboratories, with early implementations being used in today's commercial applications.

Mobility

One of the major trends in communications during the 1990s is the explosive growth of wireless services. Driven by the needs of a mobile society, greater availability of wireless spectrum, and technologies that allow increasingly more efficient and cost-effective use of the spectrum, wireless services will continue to expand rapidly.

Another trend in serving mobile users is the concept of a personal number that follows users no matter where they are, if they wish to be reached. The first generation of such services has been available for a few years. The next stage in their evolution is likely to link wired and wireless access to a user via a single number.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement