Microsoft's goal to provide a unified communications infrastructure for the enterprise moved forward Tuesday with the release of a private beta of software it sees as its communications hub.

The company released Office Communications Server 2007 to about 2,500 IT professionals in a private beta, said Paul Duffy, a group product manager at Microsoft.

It's the first time Microsoft has offered software for making voice over Internet Protocol (VOIP) part of integrated communications services alongside corporate instant messaging, e-mail, and video conferencing all running on one IP network, he said.

Office Communications Server 2007 runs in conjunction with Office Communicator 2007, which is the accompanying desktop software.

In July, Microsoft announced a strategic alliance with Nortel Networks calling for interoperability between Microsoft communications software and networking infrastructure from Nortel. Office Communications Server 2007 also will interoperate with products from Avaya, NEC Phillips, and Siemens Communications through partnerships Microsoft has with those vendors, Duffy said.

"Customers can deploy Office Communications Server and Communicator with infrastructure they have -- with IP telephony that they might have from one of those vendors -- or they can deploy it in conjunction with an IP PSTN (public switched telephone network) gateway," he said.

Though Microsoft is working with vendors on VOIP, there is some belief in the industry that the company eventually will look to provide the entire software infrastructure for VOIP and other communications offerings. Such a move would hardly be a stretch, as Microsoft's strategy for entering new markets has often been to partner with companies that specialize in certain software until it is able to build out its own portfolio.

Microsoft does not just aim to enter the VOIP-enablement market with Office Communications Server 2007, but rather provide a software hub that will allow the various facets of network communication to interoperate, Duffy said.

For instance, by using Office Communications Server with Microsoft's Exchange Server messaging software and Outlook e-mail client, a user can respond to an e-mail received in Exchange with a VOIP call using Communications Server and Communicator, he said.

Office Communications Server and Office Communicator 2007 are expected to be available in the second calendar quarter of 2007.