BT has said that 1,300 of its telephone exchanges around the UK will support symmetric digital subscriber line within 12 months.
For many businesses SDSL is more suitable than asymmetric digital subscriber line (ADSL) because it allows them to send data at the same high speed as they receive it.
BT said it would have around 300 exchanges capable of supporting SDSL by the end of March, and would upgrade a further 1,000 in two stages from April.
Most of the new SDSL exchanges are in urban areas that serve large numbers of businesses, although some serve remote areas with a large cluster of businesses, such as business parks.
Other telecom suppliers are struggling to provide SDSL outside the biggest cities. Bulldog, BT’s main SDSL rival in London, has not yet announced any plans to offer SDSL services outside London, despite its acquisition by Cable & Wireless last year as part of C&W's DSL expansion strategy.