DSL :: THE BASICS

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DSL Basics

DSL stands for "Digital Subscriber Line". The DSL technology uses existing copper telephone lines to deliver high-speed data services to businesses and homes.

Only for geeks: There are many variations of DSL, including ADSL, HDSL, IDSL, R-ADSL, SDSL and VDSL. The only two you realistically need to know about are ADSL and SDSL. "A" stands for "asymmetrical" and "S" stands for "symmetrical". The first one is often marketed as "DSL for home" and the second one as "DSL for business".

Most home and home-office users will end up subscribing to the "asymetrical" flavor of DSL, called ADSL, which happens to be much cheaper. "Asymmetrical" means that uploads are not as fast as downloads. Is this essential for you to have fast uploads? You have to decide yourself. You need fast upload speed if you are regularly doing a lot of the following:

Sending emails with large attachments from your computer.
FTP'ing or copying your local files to a remote computer or a network disk to which you are connected via DSL.
Running a web server on your DSL line.

On the other hand, if your typical activities are described by these items, you may never need the more expensive SDSL option:

Surfing the Internet
Downloading stuff (music, movies, software)
Chatting
Receiving email

In case you haven't noticed, the first group describes functions that are more typical in a business environment, but not so typical for home users. The second one, by contrast, describes activities of a typical home user.

If you want to get a better idea of what you can "get out" of a DSL line, feel free to use our calculator.

Pre-requisites

To be able to use a DSL connection, you will need a network card and a DSL modem - that device will let you connect, through a regular phone line, to the ISP providing you with DSL service.

Network cards are typically built into all modern computers (including laptops), but if your computer lacks one, you should establish it beforehand and order a card. Most network cards cost between $25 and $100.

Typically, your ISP will provide you with a DSL modem, although the cost may be added to your first month's bill (ask your ISP).

The Installation Process

Installation used to be the biggest source of customer complaints when DSL services were launched in the late 1990's. In the last few years procedures have improved significantly, but you still shouldn't expect next-day service.

Your ISP will arrange for the local telephone company to come over and do whatever they have to do with the line - don't worry about that part, just find an ISP that offers a good service. Next, your ISP may either send a technician or send you a ready-to-use modem with instructions.

If your ISP and your phone company are the same, these two separate steps may be combined into one. And, if you are lucky and your telephone line has previously been used for DSL service, the first visit may not even be necessary.

Pricing

Pricing can vary depending on the speed and other factors. Normally, for residential consumers who do not require very high speeds it's well below $100. Note, however, that the service usually carries an installation charge and you may be required to buy a router/modem/hub (if this is the case, the company should offer the equipment). Additionally, if your computer doesn't have a network card, your ISP might ask you to purchase it before you can use the service. Most cards cost from $30 to $100.

Limitations

One serious limitation should be noted: DSL is a distance-sensitive technology. This means you have to be located within a certain distance (about 3 miles for most DSL flavors) from the central office ("CO") you are connecting to. It's usually not a problem in large cities, but could be an obstacle in a rural area. Make sure you check with your ISP that your building is close enough to the data center. The last thing you want to do is to wait around for a few weeks before they finally tell you that you are out of their service area.

DSL: Summary

Advantages:
High speed; Amazing value for the speed; "Always on" connection; Flexible solutions (possibilities for web hosting on DSL line, virtual private networks).

Disadvantages:
Rarely available to consumers in rural areas; Symmetric DSL is more expensive

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