BT has launched SIP trunking in a number of countries that deliver a clear migration path to unified communications.

The UK based communications provider said that its Onevoice’s SIP trunking provides full connectivity between domestic country voice services and the company’s Onevoice global VPN, to help customers reduce telephony costs and deploy converged applications.

The service offers local numbering for both outgoing and incoming call traffic that can be delivered anywhere on a user’s network.

By utilising SIP trunking, customers can reduce rental for access lines, reduce call costs, and improve collaboration for users, whether they be office based, on the move or based remotely.

It is already available in the UK, and will be rolled out to the Netherlands, Belgium, Germany, France and the US in the coming months, with further regions, including Spain, to follow.

BT has also attained the global Microsoft qualification of Onevoice for Microsoft Office Communications Server 2007 R2.

The telecom firm has collaborated with Microsoft to connect voice services directly from Office Communications Server 2007 R2 to the former’s Onevoice globally.

Office Communications Server 2007 R2 users can now streamline communications by combining presence and instant messaging interoperability with BT Onevoice conferencing, and software-powered voice over IP in a single, unified platform globally.

BT Global Services vice president of Global Portfolio Neil Sutton said that SIP trunking gives customers the capability to introduce collaboration applications which increase productivity and save cost.

"The Microsoft qualification will open the door to further developments within the combined BT and Microsoft portfolio, creating a platform for innovation inside BT Onevoice all in a security-enhanced global environment," Sutton said.