Microsoft is to release a public beta of its VoIP server software by the end of this month. The company is already asking for potential users to register for the beta version on the Microsoft website.

Office Communications Server will compete with hardware and software products from the likes of Cisco and Avaya. Microsoft, however, is hoping to score with users by integrating Office and Exchange 2007 with the new server. For example, users could launch a VoIP call by clicking on a person's name in Microsoft's Outlook email program or its SharePoint Server 2007. the company said. The embedded "presence" technology could determine whether a person is busy or not. Other options include web-based audio and video conferences.

Enterprises are adopting VoIP to reduce their phone bills, although concerns remain over deployment, reliability and voice quality.

Microsoft said companies would not have to rip out their existing PBX phone networks. Communications Server 2007 interoperates with PBX networks through SIP - the protocol used for VOIP calls - and works with different phones, devices and management tools, Microsoft said.