Easynet has become the first competitor in the DSL market to connect a customer to its own equipment at a BT local exchange, in a process dubbed "unbundling the local loop"
By linking their equipment to BT's local exchanges, rival companies gain access to the so-called "last mile" of copper wire, enabling them to compete with BT on price.
The trial installation is taking place at BT's Battersea exchange in London.
Eddie Murphy, senior consultant at Analysys, described the event as "interesting and encouraging".
When the majority of commercial unbundled services are launched in June (some providers including Redstone expect to launch in April), he believed they were certain to speed up acceptance of DSL services.
But he warned that there was unlikely to be any real effect on the market before the end of Q3.
Murphy said that the UK unbundling process was proving more complex than in other countries and cautioned that the "hideously complicated" trial rollout was likely to be constrained by the availability of trained engineers.
Expensive bandwidth as a result of delayed rollouts could then put British companies at a disadvantage in e-commerce.
Justin Fielder, local loop unbundling manager at Easynet, said he expects around 1,000 of BT's 6,000 local exchanges to be equipped for unbundling by the end of the year.
Murphy was less bullish; saying a Forrester estimate of 220,000 DSL installations in the UK by the end of this year was optimistic given the slow start to the roll out. He suggested estimates of 100,000 users were likely to be nearer the mark.