Broadband - ADSL and Cable - How does it work?

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I am still using dial-up and have no idea what broadband actually is. What is it really, and how does it work?
G Roberts, Aylesbury

Broadband allows you to connect to the Internet at much faster speeds than a standard dial up connection.

Broadband has many advantages to dial up, including faster data transfer, free phone line and better value for money.

There are several ways in which you can get a broadband Internet connection. The most popular being ADSL and Cable though you can also connect via Wireless or Satellite.

What is ADSL?

ADSL stands for Asymmetric Digital Subscriber Line. Put simply a digital line through your existing telephone connection. ADSL works by splitting your existing telephone line signal into two, one for voice and one for data.

ADSL broadband can connect you to the Internet at speeds of up to 8Mbps (or up to 22Mbps with Local-Loop-Unbundled services) with a typical upload speed of around 256Kbps to 448Kbps. ADSL is called 'asymmetric' because the download and upload speeds are not the same.

ADSL broadband is very easy to set up. No extra cables or lines need to be installed as long as you already have a working BT telephone line. Usually you will be sent a micro-filter and an ADSL modem with all the necessary connection cables. It's a simple process to plug everything together and get going.

ADSL broadband is available from a range of different Internet Service Providers. Whichever ISP you choose your service will be connected through a BT Exchange - that may or may not have also been unbundled by the ISP. There is now over 90% coverage of ADSL in the UK.

What is Cable?

Cable broadband connects you to the Internet via a local cable TV line. Fibre optic cable buried underground is used to carry telephone, television and broadband.

Cable broadband connection speeds range between 1Mbps up to a massive 20Mbps, though in theory a cable connection could transfer data at up to 30Mbps.

If you do not already have a cable TV service installed in your home cable broadband connection usually involves a cable being installed from your house to the nearest cable point in your street. If your street does not currently have a cable line installed (currently only 46% of the UK is covered), you will not be able to get cable broadband (although the availability of cable is increasing and you may be able to get it in the future).

Once the cable line has been installed to your house, connection to the Internet involves either a cable modem or a set-top box. You can choose to have a sole Internet service or a combination of cable products including Internet, TV and telephone.

There is now only one main cable ISP in the UK: Virgin Media (who bought out NTLTelewest). Cable broadband has a 46% coverage of the UK.

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