HVAC Control in the New Millennium.pdf - HVAC.Amickracing

Building Automation, Wireless Technology and the InternetFigure 9-2. Internet connections.United States was just 39,000. In contrast, there are tens of millions ofconsumers around the world connected to the Internet via dial-upmodems.A lack of standards has impeded wider cable and DSL availability,but that should change soon. Growth is projected at 1000% ormore per year for both technologies in the near future.Dial-up connections are cheap but slow. Frame relay and T1/T3lines are fast but expensive. Alternatives include speedy, affordableDSL services or cable with fast performance and even lower prices.While cable TV lines are available to more than 100 millionNorth American homes, only 20% of these can get cable modem service.That number will grow as cable companies offer two-wayfiberoptic networks that deliver more TV channels as well as highspeedInternet connections.Cable services can deliver connection speeds at least 10 timesfaster than a 56-kbps modem for about twice the price of a typicaldial-up account.Getting a cable modem requires a PC with an Ethernet card,which the cable company can supply and install. The cable companywill often lease the modem as part of the monthly fee. Most cablesystems offer always-on service that does not tie up a phone line.About 15% use telco return, which requires a standard dial-up line tosend data from your PC to the Internet.A Web page that takes several minutes to download with a 56-©2001 by The Fairmont Press, Inc. All rights reserved.