Innovation with Impact
Apr 1, 1997 12:00 PM, C. William Day, KBD Planning
The world of information technology is changing so rapidly that it is difficult even for experienced technology professionals to stay abreast of the latest innovations. Raw computer processing power doubles approximately every 18 months, and Ethernet network speeds have moved from 10Mbps to more than 100Mbps.Yet, with these increases in computing power and communication bandwidth, most local-area networks (LANs) still have difficulty dealing with video resources.
The reason is simple-one stream of broadcast-quality video can bring even the most sophisticated LAN to its knees. In digital form, broadcast video creates a 270Mbps per second stream of information, and this bandwidth is just for the video portion of the signal. It does not take into account the audio information sent with the information stream.
For many districts, the answer lies in software, not hardware. Some manufacturers offer a parallel network strategy that brings full-motion, broadcast-quality video and stereo audio to LAN stations with no degradation in performance or video quality. This solution adapts to industry-standard wiring plans and works with level 3 or 5 twisted-pair wire, multimode or single-mode fiber-optic cable, as well as coaxial cable. To make use of an existing infrastructure or to make the most efficient use of a new infrastructure, the video and data LAN signals can be run in the same 4-pair cable. This scheme works in installations that run directly from the main distribution frame (MDF) to the destinations, as well as larger systems that use intermediate distribution frames (IDFs).
Fiber-optic cable is another way to transport the audio and visual portion of the signal. Multimode, 62.5/125-micron fiber terminated with ST connectors at both ends will be the most common type used for inter-building distribution. The system requires one strand of fiber home-run to each destination from the MDF to deliver the audio and visual.
The parallel network technology enables traditional video resources, such as VCRs, laser-disc players, cameras and cable television, to be shared as easily on a video LAN as CD-ROM servers and printers are on data LANs. The control is through a piece of software that resides on the server, creating a plug-and-play solution.
This form of PC server-based multimedia distribution network lets educators and students access, integrate and manage a wide array of information and communication resources on demand from a PC with a mouse. It provides a distributed client network solution for schoolwide, districtwide and campuswide implementation. It will deliver audio, video (analog or digital) and standard data applications to any PC over LANs and WANs. At the heart of the system is a server that supervises all network applications and media control using a TCP/IP-based management system.
From their desks, teachers and students can move seamlessly among multiple media. This can be accomplished from a live video conference to videotape to videodisc to the Internet to a CD-ROM, all through a common user interface-the personal computer. In addition, there is no need for teachers and students to rearrange technology resources or learn multiple systems.
The TCP/IP solution helps decrease the overall cost of educational technology by letting educators leverage their current investment in existing audiovisual resources while taking full advantage of emerging technologies. It eliminates the need to buy duplicate equipment for each classroom.
The system scales easily to enable interactivity with remote sites, requiring only that each remote location be equipped with dedicated Internet service and interactive video connectivity.
Because many school buildings, especially those built in the past several years, have Category 3 and/or coaxial wire already pulled throughout the building, most of this existing wire can be used to accommodate current needs. However, if rewiring is necessary, the average price of Category 5 wire today is 22 cents per foot. Category 3 wire is approximately 11 cents per foot, while fiber is about $1.10 per foot. In the case where school buildings may already have a data network in place, a district can use this network for video control.
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