ADSL in the UK

ADSL was introduced to the UK in trial stages in the late 1990s and a commercial product was launched in 2000. In the United Kingdom, most exchanges, local loops and backhauls are owned and managed by BT Wholesale, who then sell on connectivity to ISPs, who provide the actual connectivity with the Internet (in most cases), telephone support, billing and added features. BT currently operate 5591 exchanges all over the UK with the vast majority being enabled for ADSL. Only a relative handful have not been upgraded to support ADSL products - in fact it is under 100 of the smallest and most rural exchanges. Some exchanges, numbering under 1000, have been upgraded to support SDSL products. However, these exchanges are often the larger exchanges based in major towns and cities so they still cover a large proportion of the population. SDSL products are aimed more at business customers and are priced higher than ADSL services.

Up until the launch of "Max" services, the ADSL packages available from BT Wholesale were known as IPStream Home 250, Home 500, Home 1000 and Home 2000 (contention ratio of 50:1); and Office 500, Office 1000, and Office 2000 (contention ratio of 20:1). The number in the product name indicates the downstream data rate in kilobits per second. The upstream data rate is up to 250 kbps for all products.

For BT Wholesale ADSL products, users initially had to live within 3.5 kilometers of the local telephone exchange to receive ADSL, but this limit was increased thanks to RADSL (Rate Adaptive Digital Subscriber Line), although users with RADSL may have a reduced upstream rate, depending on the quality of their line. There are still areas that cannot receive ADSL because of technical limitations, not least of which networks in housing areas built with aluminium cable rather than copper in the 1980s and 1990s, and areas served by optical fibre (TPON), though these are slowly being serviced with copper.

In September 2004, BT Wholesale removed the line length / loss limits for 500 kbps ADSL, instead employing a tactic of "suck it and see" — enabling the line, then seeing if ADSL would work on it. This sometimes includes the installation of a filtered faceplate on the customer's master socket, so as to eliminate poor quality telephone extension cables inside the customer's premises which can be a source of high frequency noise.

Following successful trials, BT announced the availability of higher speed services known as BT ADSL Max and BT ADSL Max Premium in March 2006. BT made the "Max" product available to more than 5300 exchanges, serving around 99% of UK households and businesses.

Since 2003 BT has been introducing SDSL to exchanges in many of the major cities. Services are currently offered at upload/download speeds of 256 kbps, 512 kbps, 1 Mbps or 2 Mbps. Unlike ADSL, which is typically 256 kbps upload, SDSL upload speeds are the same as the download speed. BT usually provide a new copper pair for SDSL installs, which can be used only for the SDSL connection. At a few hundred pounds a quarter, SDSL is significantly more expensive than ADSL, but is significantly cheaper than a leased line. SDSL is marketed to businesses and offers low contention ratios, and in some cases, a Service Level Agreement. At present, the BT Wholesale SDSL enablement programme has stalled, most probably due to a lack of uptake.

In 2005 Northern Ireland became the only European geographic region with 100% broadband coverage and one of a few outside Asia, this was achieved by a partnership between the Northern Ireland Department of Enterprise, Trade and Investment and BT Northern Ireland.

In 2006, the UK market has been about convergance and takeovers. Talk Talk threw down the gauntlet by offering so-called ‘free’ broadband along with their telephone package at around £20 a month. Rival, Orange (formerly Wanadoo) responded by offering ‘free’ broadband for mobile customers who pay more than £30 a month. Many other smaller ISPs have responded by offering similar bundled packages. O2 also entered the broadband market by taking over LLU provider BE, while Sky had already taken over LLU broadband provider Easynet. In July 2006, Sky entered the broadband arena by announcing 2 Mbps broadband to be available free to Sky customers and a higher speed connection at a lower price than most rivals.