width available in three or more ISDN BRI lines to create a super-rate, two-way channel for transporting the video and audio signals, as illustrated in Figure 6-3. Three ISDN BRI lines provide six 64 Kbps channels for an aggregate channel of 384 Kbps, perfectly adequate for high-quality videoconferenc- ing. These devices range in price from as low as $6,000 to as high as Figure 6-3 Three ISDN BRI circuits are bonded to form a 384 Kbps circuit. To videoconferencing unit 384 Kbps 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 Chapter 6 $80,000. And while many people would turn up their noses at the thought of using ISDN, let it be known that far and away the vast major- ity of all videoconferencing rooms use ISDN for network connectivity, as opposed to some other protocol. Automatic Call Distribution (ACD) Another significant application for PRI is call routing in the call center environment. Ultimately, call centers represent critical decision points within a corporate environment, and the degree to which they are suc- cessful at what they do translates directly into visible manifestations of customer service. If calls are routed quickly and accurately based on some well-designed internal decision-making process, customers are happy, and the call center provides an effective image of the corporation and its services before the customer. Automatic call distribution, or ACD, is a popular switch feature that allows a customer to create custom routing tables in the switch SO that incoming calls can be handled most effectively on a call-by-call basis. The ACD feature often relies on information culled from both corporate sources and the SS7 network's SCP databases, but the ultimate goal is to provide what appears to each caller to be customized answering. For example, some large call centers handle incoming calls from a variet