ADSL - Asymmetric Digital Subscriber Line

How is this long description made up?


The main telephone companies, such as British Telecom, will rent you a telephone line which they call a 'subscriber line'. The type that is used for Internet connections is 'digital' - so it becomes a 'Digital Subscriber Line' (DSL for short).

Now the type that is rented to most people is 'Asymmetric'. This means the line works at different speeds depending on which direction the data is travelling. If its coming from the Internet to your computer then it is fast - like a motorway. If you are sending data from your computer to the Internet - then it is much slower - like a country lane. This is not a problem for most web users because we tend to download at high speed (e.g. video news) compared to posting data (e.g photos on Flickr, Blogs, Forums etc.)

If you *really* want high speed *both* ways then it is possible to rent a 'Synchronous Digital Subscriber Line' (SDSL) but it is more expensive and is mainly used by large businesses.