BT customers in Cardiff will be the first in the UK to have their residential lines migrated onto BT's 21st Century Network (21CN).

BT said the process will begin in late November and there will be three phases in Cardiff. "Phase one will run from November 2006 to March 2007, involving upgrading voice services for 10 percent of customers in Cardiff and the surrounding area," BT said. "Phase two, from April to mid-May 2007, will deliver a further 10 percent, and by Phase 3 in the summer of 2007, all 350,000 customer lines will be upgraded."

After the Cardiff upgrade, BT and the other communications providers will start an in-depth review before migrating the rest of the UK's residential customers, some 30 million lines from over 5,500 telephone exchanges, starting in January 2008.

BT indicated that 21CN will be rolled out to smaller business customers following the review. "Private-circuit-based services, which typically support business-critical apps [for large corporates], will not migrate on to the new network until much later in the programme," it added.

Chris Smedley, managing director of telecoms solutions provider Geo, said 21CN will provide cost savings for BT over its entire infrastructure, but questioned whether it will deliver a better service for home users.

"They should announce the user testing results – they should say how elements of this service will impact the customer," Smedley said. "How will they implement last-number redial for instance?"

BT added that it will let consumers and businesses "know when the migration to 21CN will happen in their area, how it will be done and what it means for them".
BT said further details will be announced in October and that corporate customers will "receive more detailed communications directly from their comms providers, including the comprehensive testing regime for customer equipment". A detailed list of all customer premises equipment scheduled for testing is available here.