Company British Telecom (BT) has expanded its BT Onevoice converged voice platform, in a effort to boost the deployment of VoIP communications applications to the desktop in large, enterprise type businesses.

The Company has started works on SIP trunking in different countries, which it is being declared will deliver a migration pace for business VoIP solutions in frames of unified communications concept.

SIP trunking delivers connectivity between local, regional country voice services and BT's Onevoice global VPN to assist customers deploy full scale converged applications.

It provides an opportunity for business VoIP general implementation to staff and administration, having existing PBX, to make and receive calls through the public switched telephony network (PSTN), over the corporate IP networks.

BT said the service offers local numbering for both outgoing and incoming call traffic, which can be delivered anywhere on a user's network.

This unified communication enabled concept is already on market in the UK, the services will be moved out to the Netherlands, Belgium, Germany, France and the US in the next months, with further regions, including Spain and Portugal to follow. As BT officials stress in their statements, business VoIP application by utilizing SIP trunking makes customers drastically reduce rental for access lines, reduce call costs, and delivers smooth inter-users collaboration, whether they be office based, traveling or based remotely.

BT Onevoice platform is fully certified to deliver SIP trunking service for interconnection with Microsoft Office communications Server 2007 R2.

With the two products users can streamline communications by combining presence and instant messaging interoperability with BT Onevoice conferencing, and software- powered VoIP in a single, unified platform.