Internet Services - About Broadband and ADSL
ADSL - An Overview
ADSL stands for Asymmetric Digital Subscriber Line. A twisted copper pair of wires are transformed between a local telephone exchange and a Customers telephone socket into a high-speed digital line.
ADSL is not unlike a standard Kilostream connection as in there are no additional telephone calls and this is an 'always on' service. ADSL is exchange dependant and the speed can not be guaranteed. You can have access to the Internet whilst utilising the same line for say faxing or having a telephone conversation. Most of all you are always connected so there's no dialing up required and therefore no phonebill.
This is called "asymmetric" because it moves data more quickly from the exchange to customer than it does from the customer to the exchange. This technology is thus particularly suitable for applications where customers expect to receive more data than they transmit i.e.: using the World Wide Web, Intranets, and use of digital audio-visual material.
ADSL allows dedicated bandwidth that can be up to 62 times faster than ISDN. In addition, this technology uses your ordinary phone line but doesn't restrict use or tie up the line.
How fast is ADSL ?
ADSL comes in three flavours, providing variable speeds to allow users to best match requirements to budgets.
- ADSL S500 allows 256k upload and 500k download
- ADSL S1000 allows 256k upload and 1Mb download
- ADSL S2000 allows 256k upload and 2Mb download
This is 10 to 40 times faster than today's typical modems.
How does ADSL work?
ADSL operates over a standard telephone line. The signal is carried by two ADSL modems - one in the local exchange and one in the clients premises. The modems are designed in a such way as to utilise fully the capabilities of the copper line therefore achieving much higher data rates. A 'splitter' separates the signal from the ADSL sign, meaning that telephone calls can still be made at the same time as data is being sent or received.
What can it be used for?
- Internet access - The access speeds available with ADSL make it practical for web sites to carry more multimedia rich information such as embedded video clips, animations and good quality audio - significantly enhancing the online experience
- Intranet access - Fast access to the Intranet makes teleworking an attractive option - which in turn can bring benefits to both the organisation and the individual
- TV based services - ADSL can be used to deliver interactive applications to the TV, such as real time video and audio, home shopping and home banking
- Future services - ADSL will be the catalyst for a wealth of new information, education and entertainment services
Who will be able to take advantage of ADSL ?
The local exchange needs to have been provisioned with ADSL capability. There is a phased roll out in place, which means that not everyone will be in a provisioned exchange area location.
Because ADSL is distance dependant, the end user needs to be located within a certain distance of the exchange. This distance is typically 3.5Km and approximately 80-85% of the UK live within this distance of their exchange.
So where is ADSL available?
The service is available from over 400 exchanges including the following locations:
Birmingham, Belfast, Cambridge, Cardiff, Coventry, Edinburgh, Glasgow, Leeds, London, Manchester, Milton Keynes and Newcastle.