BT begins trial of extended-reach ADSL

By Alun Williams

Posted on 27 Feb 2003 at 13:17

BT is bidding to stretch its ADSL broadband service over a greater distance. The goal is to put more people within the reach of phone line-based broadband.

Currently, 5.5km is the maximum distance for receiving ADSL services from a local exchange. BT, however, is now trialling ADSL services over a distance of 6km. While its still at a very early stage, customer trials are due to begin at the end of March.

The importance of this whole issue is that the greater the distance supported, the more people can benefit from their local exchange being ADSL-enabled and more people have more choice for broadband. ADSL is the provision of broadband over PSTN (public switched telephone network), as opposed to the less-prevalent cable or satellite-based services.

The challenge facing BT - involving the basic laws of physics - is to preserve effective bandwidth over greater distances. 'We have to make sure the impact on quality is not so great that the product wouldn't be commercially viable,' said a BT spokesperson. They emphasised that no firm timetable yet existed for the possible implementation of the service

Issues to be met include the guaranteeing of contention ratios. For longer distances, the same bandwidth may be available to fewer customers, potentially increasing the service costs per user for ISPs.

Originally, a 3km limit existed for the provision of broadband from ADSL-enabled exchanges.

BT Wholesale has just brought its ADSL-based business services in line with existing domestic offerings. It has extended the reach of its 500Kbits/sec 'BT DataStream Office' service to 5.5km from a local exchange.