xDSL Technologies

 

xDSL

xDSL or *DSL refers to all variations of the DSL family or technologies - the technology that enables broadband Internet access to be delivered to your house through a standard phone line.

DSL, Digital Subscriber Line technology uses existing Plain Old Telephone (POT's) lines to transmit and receive high speed Internet data. Unlike a dial-up modem, DSL is always connected, eliminating the connection delay. DSL is up to 50 times faster than a dial-up modem and up to 12 times faster than ISDN (the original digital technology). DSL is used for Internet access, E-mail, Web Site Hosting, Corporate Intranet and Virtual Private Networks.

How Does it Work?

A DSL router is installed at your location and connected to either a network card in your Personal Computer (Pentium or Mac) or directly to an existing Ethernet network. The DSL Router is equipped with a firewall or packet filtering and is configured to hide your local computers from the Internet for security.

In the telephone company central office or exchange the DSL line is connected to a DSLAM (Digital Subscriber Line Access Multiplexer). The DSLAM is connected through routers directly to the Internet Backbone.

DSL Flavors and Speeds

ADSL (Asymmetrical Digital Subscriber Line) is faster in the return (download) than send (upstream) direction. Upstream speeds are usually 128Kbps to 1.088Mbps while downstream speeds are up to 8.192Mbps. ADSL is typically used in residential-class service and may share an existing telephone line with standard telephones.
SDSL (Symmetrical Digital Subscriber Line) SDSL is designed to provide high bandwidth in both directions. This is suitable for many business applications such as e-mail, file transfers and Web Site Hosting. Typical speeds are 144kbps to 1.544Mbps. There is also:

• HDSL - High bit-rate Digital Subscriber Line
• IDSL - ISDN Digital Subscriber Line
• VDSL - Very high bit-rate Digital Subscriber Line

Distance

The speed that can be obtained using DSL is dependent on the distance (length of cable) between the user and the telephone company central office (C.O.) or exchange and the thickness of wire used by the telephone company. Typical maximum distances are as follows:
1.5Mbps - 10,500 feet (2 miles)
1.0Mbps - 12,300 feet (2.3 miles)
768Kbps - 13,500 feet (2.5 miles)
384Kbps - 22,500 feet (4.3 miles)
144Kbps - 35,000 feet (6.6 miles)*
*In many areas 144 Kbps (IDSL) is provided over digital carrier and fiber optic cable allowing unlimited distances to be obtained.

As new technologies and equipment are placed into service, speed and distance will continue to increase.

				xDSL FAQ's

What are the benefits of DSL?

A: Four key benefits are: ·

• DSL is faster than other remote access technologies such as analog modems, ISDN, cable modems, or wireless solutions.
• DSL provides secure, continuous access over a dedicated phone line to each home or business customer - no time is wasted with dial-up routines.
• DSL is cost-effective to implement and to manage.
• DSL utilizes the existing copper wire infrastructure, therefore it can be deployed almost everywhere.

Q: Why are people so interested in DSL?

A: DSL eliminates many of the obstacles that prevent Internet users from making the most of their online access. Dial-up hassles are eliminated with DSL's "always on" dedicated connection. Also, DSL's speed and reliability are particularly attractive, given the comparatively low cost associated with this option. As awareness of DSL's benefits grows, demand is driving DSL providers to rapidly scale their networks.

Q: What factors should I consider in determining my Internet access needs?

A: You should consider several factors: · The amount of time you spend online · The activities you perform on the Internet · Your need to support multiple-users through a single connection · The overall cost of basic dial-up service versus faster, less cumbersome access methods

Q: Is the cost of DSL going to decrease? How soon?

A: DSL is an emerging technology, therefore it is impossible to predict the market forces and timing that will influence future pricing. Nevertheless, DSL is an exceptional value, compared with other means of online access, and it has every potential to remain an exceptional value.

Q: Can I view online video clearly with DSL?

A: Video works exceptionally well on DSL, depending on the speed of your DSL connection. Most movie trailers and high bandwidth videos are designed for 80-128 Kbps speeds. These are well within the capacity of DSL, which is up to 12 times faster than 128 Kbps.

Q: If I get DSL today, can I easily get faster service in the future as the technology improves?

A: Typically, yes. For example, if you purchase a lower speed DSL, the accompanying equipment can support you as you upgrade to faster speeds. When you're ready to trade-up to a higher-speed, your DSL provider will work with you to determine which options may be available at your location.