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Hybrid fiber-copper network delivers digital video.

In a project which personifies the innovative approach to educational reform in this country, a "special needs" school district in New Jersey will put grade school children on-line in 1993 by letting them access mixed media data over the phone.

Using a new technology called carrierless amplitude and phase (CAP), parents and students in densely populated Union City, N.J., will "dig for knowledge" over a cost-effective network to be deployed by New Jersey Bell. CAP is a transmission technology developed by AT&T Paradyne that can implement full motion video over Bellcore's copper-based asymmetrical digital subscriber line (ADSL).

The idea originated last year in a memo from Bellcore's Lewis Gomez and Charles Judice. Circumstances were right for such an experiment. Union City Mayor and State Senator Robert Menendez was interested in new telecomm technology to improve education. The school district was consolidating two elementary schools, rewriting curricula and renovating the former St. Michael's parochial school. As part of the renovation, New Jersey Bell will rewire the building using a combination of fiber optics, coaxial cable and copper wire. These elements, together with an offer of AT&T's technology, resulted in the birth of a new distance learning project.

Bell Atlantic and AT&T announced in October 1991 that interactive voice and data plus full motion video would be sent to students' homes over standard copper phone lines using CAP-based ADSL during the 1992-93 and 1993-94 school years. Teachers, students and parents will access information and videos provided by third parties and stored in bilingual libraries and large-scale computer databases.

The project team will work with the Center for Children and Technology (CCT), located at Bank Street College in New York City, on both the trial and new multimedia curricula.

"As designers create multimedia simulations and databases, they will need to provide new kinds of 'information organizers'--methods for accessing and linking visual and auditory information," points out Kathleen Wilson, director of multimedia design.

In cooperation with the telco, CCT staff will search for resources. Bell Atlantic encourages computer vendors to find or develop software solutions that allow users to create multimedia displays to enhance the documentation-based video programs they access. CCT hopes the mainframe computer and up to 190 PCs for school and home use will be provided by commercial participants in the trial. Teachers will have high-end workstations to enable them to author lesson plans.

"Getting parents involved is crucial to the project's success," says Frank Vaccarino, assistant superintendent of schools. "So we will provide them with access to multilingual data on immigration, documentation, and citizenship contained in a special 'port of entry' class."

Fred Carrigg, director of academic services for Union City schools, explains that during the first year, meetings and home visits will be arranged for parents who will be project participants in the second year.

During school renovation, New Jersey Bell will use fiber-optic cable for both internal wiring and to connect the building to the multimedia server at the Union City exchange. From the exchange, existing copper telephone lines will connect students' homes.

"This allows us to meet our objectives for a cost-effective trial," explains John Grady, manager of video services development at Bell Atlantic.

"We were looking for a way to implement VCR-quality television that met Bellcore's requirements for ADSL, and AT&T Paradyne offered CAP. It seemed like a good solution and met most of our objectives without an immediate large investment. We see CAP as an evolutionary technology we can use as we begin to replace copper with fiberoptic cable," Grady adds.

The strength of CAP lies in its ability to provide bandwidth-limited signals compatible with other telephone services. At the customer premises the CAP signal is demodulated and is routed to a video codec and controller that let the user display mixed media signals on a PC or TV screen. CAP also provides an interactive channel centered at 100 kHz to enable subscribers to communicate with the database. Because of its conservative bandwidth occupancy, other services such as voice telephone can exist on the same pair of wires as CAP.

At the telephone exchange, incoming requests from students are switched to the multimedia server over a DS1 link. A connection is established between the user and the library database. Based on the data received, the server and the central computer locates the desired program and puts it on-line. The digital video signal is processed and switched via a DCS (digital cross-connect system).
COPYRIGHT 1992 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1992 Gale, Cengage Learning. All rights reserved.

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Title Annotation:carrierless amplitude and phase
Author:Stewart, Alan
Publication:Communications News
Date:Dec 1, 1992
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