What Is DSL?

by: Toh Poh

DSL stands for Digital Subscriber Line. It is a service that makes use of existing copper telephone wires for delivering data services at high speeds. It does not hamper the existing telephone line. You can surf the Internet and talk on the phone, simultaneously.

DSL offers speeds that are around 5 to 25 times higher than a typical 56Kbps (56 kilobits per second) dial-up connection. It is an always-on type of connection. This implies that websites would load quickly, downloads would be faster, buffering of videos would be fast and smooth and the domain of online games would have no limits.

Based on the types of service, DSL can be categorized in three divisions: ADSL, IDSL, and SDSL.

ADSL stands for Asymmetric Digital Subscriber Line. It offers download speeds of 1.5 Mbps and upload speeds of 384 Kbps. In order to acquire a ADSL connection, your location has to be within 3 miles of your local telephone office. Also, a DSL router is needed for this type of connection. [note by russ: as of 2008, DSL can provide over 6 Mbps.]

IDSL is a ISDN Digital Subscriber Line service which requires an ISDN router. It provides a connection speed of 144 K. in this type of connection distance is not a component to be considered.

SDSL means Symmetric Digital Subscriber Line. The speeds available under this type of DSL connection depends on the distance between your location and your local telephone office. The speed of downloads and uploads can go up to 1.1 Mbps.

Advantages of DSL

No installation of new wires is required. DSL uses the present telephone line to connect to the Internet. It provides extremely fast connection. Depending on the offer, you would not even have to pay for the DSL modem installation charges, since it is provided free by some of the companies on selection of the appropriate plan. The download rate is much higher in DSL connections. Many business organizations have gained the benefits of DSL. A DSL connection is very secure. Disadvantages of DSL The quality of your DSL connection depends on the distance between the DSL provider's office and your location. The nearer you are, the better quality connection you get. So, consumers located far from the local DSL office may face some trouble. DSL provides high speeds for downloading but upload speeds are not that good. DSL vs Cable Modems The services provided through a cable modem can sometimes slow down or get hanged. It depends on the number of users accessing that particular service. But, in a DSL connection there is no such problem. The speed of DSL is consistent and high. This does not allow any kind of conjunction on the network. It provides more security than cable modem connections. The popularity of DSL has risen to new heights which has resulted in disconnections and up-grading of cable modem connections.

Disadvantages of DSL

The quality of your DSL connection depends on the distance between the DSL provider's office and your location. The nearer you are, the better quality connection you get. So, consumers located far from the local DSL office may face some trouble. DSL provides high speeds for downloading but upload speeds are not that good. DSL vs Cable Modems The services provided through a cable modem can sometimes slow down or get hanged. It depends on the number of users accessing that particular service. But, in a DSL connection there is no such problem. The speed of DSL is consistent and high. This does not allow any kind of conjunction on the network. It provides more security than cable modem connections. The popularity of DSL has risen to new heights which has resulted in disconnections and up-grading of cable modem connections.

DSL vs Cable Modems

The services provided through a cable modem can sometimes slow down or get hanged. It depends on the number of users accessing that particular service. But, in a DSL connection there is no such problem. The speed of DSL is consistent and high. This does not allow any kind of conjunction on the network. It provides more security than cable modem connections. The popularity of DSL has risen to new heights which has resulted in disconnections and up-grading of cable modem connections.
Frequency spectrum plan for DSL technologies
author: Kaprak
ADSL splitter
ADSL splitter
ADSL splitte
Another ADSL splitter

These tiny boxes filter the high frequency ADSL signal and allow telephones, fax machines, etc. to work on the same line.
Actual ADSL spectrum, 1/2 mile from central office
Actual ADSL spectrum, 1/2 mile from central office
screenshot: Didier Misson

About The Author

Toh Poh Leng owns and operated www.dsl-upgrade-help.com. It appears to have been taken offline in 2009.