What Is Dsl?

By Author: Jennifer Davis
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DSL (Digital Subscriber Line) is a telecommunication service that transforms an ordinary phone into a high-speed conduit for data, voice and video. The service is especially available for those who are close enough to a telephone company central office that offers the DSL services. A typical DSL connection allows subscriber to enjoy speeds of up to 1.5 Mbps downlink and 256Kbps. The actual speeds vary according to the proximity of the subscriber to the central office. In addition, DSL services are on at all times, meaning that subscribers don't have to dial each time to access the internet. There are some services that allow users to use the same line for voice and data. There are a variety of DSL technologies but their availability may depend on where one is located as well as individual bandwidth needs. Here are some of them.
IDSL. This stands for ISDN Digital Subscribers line, and it is a form of DSL that uses ISDN provisioning and positioning, and can co-exist with the current analogue and ISDN services. This service is typically restricted to about 144Kbps upstream and downstream, though it may provide further reach ...
... as it not restricted by the same distant limitations.
ADSL, which stands for Asymmetrical Digital Subscriber Line. It employs two different transmission speeds, with the downstream speed being (from the provider to the subscriber) being much higher than the upstream speed (from the user to the corporate host). This service is capable of achieving downstream data rates of up to 8Mbps and upstream speeds of up to 1Mbps.
VDSL. (Very High Speed Digital Subscriber Line) the service promises speeds that are even loftier than those offered by ADSL , albeit on much shorter distances.
RADSL. Stands for Rate Adaptive Digital Subscriber Line, and it adjusts the data transmission rate to match the quality of the phone line. RADSL subscribers usually enjoy the best performance on their telephone lines and can have up to 7Mbps downstream and 1Mbps downstream.
HDSL/SDSL. (High Data Rate Digital Subscriber Line/ Symmetric Digital Subscriber Line) this one uses two standard phone lines for 1.5Mbps transmission speeds and offer the capability to combine three phones to enjoy about 2.0Mbps speeds. This service is intended as lower cost replacement for dedicated and fractional T-1 lines2.
Things are looking up for the DSL services as more people move towards the information based economy. DSL generally is a cost effective as it eliminates the need for expensive infrastructure installations, and it only needs little additional equipment. The speeds are good. DSL is mostly used in the telecommunication industry by network service providers, ISP's, as well as local and public phone companies. Universities and research facilities are also known to use the service. DSL eliminates the problems associated with alternative technologies by using existing telecommunication systems to remove the bottlenecks linked with the last mile between the provider and user. One major disadvantage of DSL is availability, as it is mostly available near the central offices of the service providers, and since the lines use copper wires, they are not compatible with fiber optic lines.