Asymmetric digital subscriber line, shortened to ADSL, is a type of internet connection that uses a home landline to provide broadband.
ADSL allows faster transmission of data through copper telephone lines. It splits the telephone connection so that frequencies not used in a voice telephone call are used for broadband.
This means that the ADSL can be used at the same time as a phone call is made, compared to the early days of dial-up internet connections.
It is the most common form of internet connection in the UK. It provides much higher bandwidth and bit rate for downstream than upstream, meaning download speeds are far quicker than upload speeds.
This means that is suitable for most of the needs of ordinary consumers, who do not generally need to upload large amounts of data to the internet, but are not suited necessarily to businesses that have significant operations online and run servers.
For these businesses, a different type of connection such as a leased line would be more capable of handling the traffic.
The speed depends strongly on how close the customer is to the local telephone exchange.
However, it is very easy to set up because it does not require any unique technology.
All the major broadband providers offer ADSL connectivity as a basic package.. According to comparison website uSwitch, BT offers it for around £24 per month including line rental, while TalkTalk offers it starting at £17.70 per month. Sky offers it for around £23 per month.
ADSL requires a telephone line, which has led to broadband packages being sold with the line rental charge separated out from the cost of the plan. Recently regulatory bodies such as the Advertising Standards Authority have clamped down on this and customers will have to be presented with a single monthly charge.