BT is planning to double the coverage of its SDSL network over the next few months by upgrading another 150 local exchanges.
The telco has asked Internet service providers to name the areas in Britain where they believe there is strong demand for SDSL.
This approach differs from BT's tactic for managing the rollout of ADSL. BT has asked individuals to express their interest in ADSL via a Web-based demand tracker.
"Customers who want SDSL should tell their service providers, and the service providers will then tell us," explained a BT Wholesale spokesman. ISPs have until 14 May to respond to BT.
Unlike ADSL, SDSL provides a high-speed link both upstream and downstream. ISPs can currently offer SDSL products from 150 local exchanges, which are mainly based in major cities such as London and Manchester.
After a long trial, BT finally launched its SDSL services last September.
According to one of the ISPs which took part in these trials, the take-up of SDSL could be better.
"BT and ISPs need to do more to promote the benefits of SDSL," said an Eclipse Internet spokesman. He added that media companies, who need to send and receive large files such as high-resolution graphics, are showing particular interest in SDSL.