xDSL Technology Overview
Early DSL Systems

The early DSL (Digital Subscriber Line) system developed for the Basic Rate Access ISDN was the first to be addressed in 1982 and 1988. DSl is designed to operate on all non-load telephone subscriber loops confirming the resistance design rule. In the late 1980�s Bellcore began researching into a new method of T1 and E1 provisioning that would eliminate repeaters and simplify the overall deployment of high bandwidth networks into the home or office. HDSL, was designed to deliver traditional T1/E1 services over unconditioned wires by placing transceivers on each end of two or three twisted pair. Next will be ADSL Service used Asymmetric Digital Subscriber Lines (ADSL) technology which provides high speed Internet access for your home/ office using your existing copper telephone line-up to 50 times faster than traditiional 28.8 modem speed. And, you won�t have to deal with busy signals or have to wait long periods of time during dial-up. Well actually you are already connected when your computer and FastAccess modem are on. (NO DIAL UP)


DSL installations began in 1998 and will continue at a greatly increased pace during 1999 in a number of communities in the U.S. and elsewhere. Compaq, Intel, and Microsoft working with telephone companies have devloped a standard and easier form called G-Lite that is expected to accelerate deployment. The fact that DSL took over ISDN was accomplished by muliplexing your telephone line into 3 separate bandwidths or frequencies currently your voice is carried over the lower frequencies (30hz to 4khz) leaving the higher frequencies or bandwidth unused. DSL technology has enabled us to utilize the higher frequencies two way data transmission at very high speeds. This way we can use the 300khz to 700khz band frequencies upstream transmission and 1000khz and above for high frequency, very high downstream service. And since we are using the bandwidth your current phone doesn�t, you can talk on the phone and surf the net at the same time. With DSL you don�t need to add an additional phone line. In other words Digital Subscriber Lines is a technology that assumes digital data and not require change into analog form and back.


















DSL Systems VS. Cable Modems

A brief comparison of DSL system to cable :

1) SERVICE : a local loop of fiber cable must be available near all residences (AREA) this is not for business users. Especially for new building or developments. This dictates that the Cable company would have to run fiber cable to all these and other new spots. (Very expensive, time consuming).

2) SPEED : Cable users are set up as a LAN so more and more people connect and surf the Web, your bandwidth or line speed diminishes proportionately.

3) SECURITY : LAN, is not a secure connection. Plain and simple.

DSL is definetly your way to go if you were looking for speed, security, and service!
Pricing the Various DSL Systems

Pricing for DSL currently, different broadband service providers are offering a variety of pricing levels and service choices. Often, the same service is offered by different service providers at various pricing points. Usually, the amount of bandwidth supported by the DSL line determines the cost to the subscriber. The small office/home office or consumer subscriber needs to determine what type of application they will be using to decide which service is appropriate for them to use. As new service providers enter the market, prices for DSL service will continue to be competitive. Today, DSL service is offered at various price points while a comparision of other Internet access methods such as 56k dial-up, ISDN and cable indicates that service charges for these other broadband technologies have stabilized. A typical monthly cost for 56k servuce supporting up to 56k downstreaming/33.6k upstream may range from $20 to $30 and may include a usage fee; a range for ISDN supporting 128k downstream/ 128k upstream is $70 to $150 plus usage (requires the additional cost of installation of another phone line to the home or business) and cable service is $30 to $120 providing a range of bandwidth from 200k to 27Mbps downstream and 33.6k to 5Mbps uptsream (the amount of bandwidth provided by cable may be unpredictable because it is a shared access technology and often it is not available in both directions. A phone line must be used in many cases to provide an upstream connection).



WHAT THIS MEANS

In a stir-crazy state almost everyone who uses the Internet from home/office can identify with today is time it takes to download or the minutes it takes for a Web pages to appear on their screen. The longer it may take you to get the information you need, sometimes you will notice that the connection is lost. Others today find that having a direct line can benefit the consumer with ease.

1) Dial-up modem (56k)= 25 minutes

2) Intergrated services digital network (ISDN)= 10.5 minutes

3) Home satelite dish= 3.3 minutes

4) Digital Subscriber Line (DSL)= 2.5 minutes

5) Cable modem= 1.3 minutes

6) T1 line= .51 seconds



Result time typically needed to download a 10-megabyte file (about the file size of all the words, except advertising, in 10 copies of your daily Newspaper).



The main virtue of DSL is that it offers higher guaranteed speeds than do cable modems. But its range is limited; people who live more than about three miles from a local switching station cannot get DSL service. And both Cable modems and DSL service provide faster transmission of data to the home than from the home on the theory that the customer would rather watch video over the Internet, for instance, than broadcast their own to the world.

For the moment, Cable modems are more readily available, and are typically a bit faster than the average DSL connection. But because each household in a given area shares the cable network, the more subscribers, the slower their connections can be. Cable executives insist that they can add capacity to maintain the speed, but customers in several markets have complained about th eslow speeds! The choice is yours.
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xDSL Overview
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