High Speed Internet
If you have internet access, it is important to know what kind of internet speed you want to purchase. High internet speed is helpful for businesses, and T1 lines are great ways to have a fast internet connection. When you connect to the Internet, you might connect through a regular modem, through a local-area network connection in your office, or through a cable modem. A growing number of people, though, are reaching the Internet through a Digital Subscriber Line (DSL) connection, a high-speed connection using the same wires as a regular telephone line. This article explains how a DSL connection manages to squeeze more information through a standard telephone line and lets you make regular telephone calls at the same time.
A normal telephone installation in the U.S. consists of a pair of copper wires that the phone company installs in your home. The pair of copper wires have lots of room for carrying more than your phone conversations. The wires are capable of handling a much greater bandwidth, the range of frequencies, than that demanded for voice. DSL exploits this extra capacity to carry information on the wire without disturbing the line's ability to carry conversations. The entire plan is based on matching particular frequencies to specific tasks.
To understand DSL, you first need to know a couple of things about a normal telephone line, the kind that telephone professionals call POTS, for Plain Old Telephone Service. One of the ways that POTS makes the most of the telephone company's wires and equipment is by limiting the frequencies that the switches, telephones and other equipment will carry. Human voices, speaking in normal conversational tones, can be carried in a frequency range of 0 to 3,400 hertz, or cycles per second. This range of frequencies is tiny. For example, compare this to the range of most stereo speakers, which cover from roughly 20 hertz to 20,000 hertz. In addition, the wires themselves have the potential to handle frequencies up to several million hertz in most cases. The use of such a small portion of the wire's total bandwidth is historical -- remember that the telephone system has been in place, using a pair of copper wires to each home, for about a century. By limiting the frequencies carried over the lines, the telephone system can pack lots of wires into a very small space without worrying about interference from one line causing problems on another. Modern equipment that sends digital, rather than analog, data can safely use much more of the telephone line's capacity. DSL does just that.
The majority of home and small business users are connected to an Asymmetrical DSL (ADSL) line. ADSL divides the available frequencies in a line on the assumption that most Internet users look at, or download, much more information than they send, or upload. Under this assumption, if the connection speed from the Internet to the user is three or four times faster than the connection from the user back to the Internet, then the user will see the most benefit.
