BT Hosted Voice is based on Nortel's Communication Server 2000 IP telephony switch and is certified by the Communications Electronics Security Group (CESG), the information assurance arm of GCHQ, for the transmission of "restricted" voice traffic.
The service already has one major, albeit anonymous, customer, and it will be opened up to others in January 2008.
"This is a platform that we're already using (with the unnamed customer). It already has 50,000 users and carries a million calls a day," Andrew Small, head of contact centers at BT Global Services, said on Tuesday. "What we are doing now is extending the platform's availability to other customers."
Small said that the nature of the platform, and its integration with21st Century Network infrastructure, will give users the flexibility to connect from home or abroad. "It also allows them to scale very quickly because, if they want to add more users to the network very rapidly, we can accommodate that," he said.
's involvement means that customers of BT Hosted Voice will be buying into Nortel and Microsoft's "unified communications" platform, which includes features like Web conferencing, instant messaging and presence technology.
BT and Nortel, which have been working together since 1990, are promising "low-risk, managed" transitions to the new product from existing products such as FeatureNet, according to Small. He also predicted that BT Hosted Voice would eventually be made available to midmarket companies and local government authorities.
David Meyer of ZDNet UK reported from London.