Hey there, and welcome to my article on just how exactly DSL works. I've tried my best to explain as much as I can within this article, but if you are serious about understanding and/or working with DSL, I'd strongly recommend that you have a read of the highly reviewed and saught after book: Fundamentals of DSL Technology

Short for Digital Subscriber Line the xDSL technology is an extremely popular type of broadband Internet connection available for most homes and businesses. Just like cable modems an average xDSL connection currently has transfer speeds of 512 kbit/sec downstream and 128 kbit/sec upstream, however speeds up to three times greater than these are available.

An xDSL modem doesn't require any extra cabling to be installed into your house, unlike a cable modem that is! The reason for this is that xDSL works using the existing telephone lines already installed, however because of the way the xDSL technology works you are still able to use the same telephone line to make calls, even whilst connected to the Internet.

There is however a drawback with xDSL technology, this is that in order to be able to use the service you must be within a specific distance from your telephone companies central office so that the signal strengths reaching your modem are within specific levels. If your too far away then there is little that the telephone company will do to help.

So how does it work?

To understand how xDSL works it is important to look at the technology behind the standard telephone. The technical term for your plain old telephone is POTS, which actually stands for Plain Old Telephone Service! When you make a telephone call your handset sends signals along the copper wires running out of your house, these signals carry your voice and are directed via the telephone exchange to the telephone handset of the person you are calling. When the POTS was originally conceived and implemented the technology was less advanced, less reliable and vastly more exensive that it is today. The result of this is that the telephone companies had to make the service as efficient as possible and had to cram together vast amounts of wires within switch boxes and switch boards. This lead to a problem as when a signal travels down a wire it gives off whats termed EMI (Electro Magnetic Interference) this normally wouldn't be a problem but due to the sheer volume of wires packed together it lead to high levels of interference on the telephone lines. This problem was overcome by limiting the frequencies of the signals used to a range just below that of a human voice, this maintaned quality but mean't that some of the subtle tones that individualise a persons voice were simply chopped off, this is why many people sound somewhat similar on the phone.

Todays technology and the introduction of digital communications has lead to major advances in the way that we communicate and this has allowed the full potential of the now dated telephone lines to be unleashed.