Microsoft last week lined up additional back-end partners it will need to support its real-time collaboration platform and VoIP client. The company plans to give corporate users a full range of voice communication features through software that supports integration between any PC-based device or service and traditional cell or wireline phones.

The partnerships, including those with Cisco and a number of telco partners, focus on support for Session Initiation Protocol (SIP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE), and the integration of traditional phone systems and the PC.

At the annual VoiceCon show Microsoft said Alcatel, Avaya, Cisco, Mitel, NEC, Nortel and Siemens will integrate call-control capabilities with Microsoft's Live Communications Server (LCS), Office Communicator 2005 desktop client and Office Communicator Mobile.

"LCS and Communicator are not worth a whole lot without the back end," says Rob Enderle, president of the Enderle Group. "They have to have the back end in place, or the other parts don't move."

SIP is lauded for its openness and flexibility, but many vendors, such as Avaya, Cisco and Nortel, balked at building pure-SIP versions of their telco gear, citing feature limitations.

Those limitations are eroding, making it easier for vendors to build integrated products.

"This allows enterprises to begin to unify LCS with other projects, such as rolling out Cisco CallManager," says Irwin Lazar, an analyst with Burton Group. "When those users discovered that CallManager did not work with LCS they were the people going to Cisco and Microsoft saying you need to figure this out quickly."

The integration of Microsoft's products with those from Alcatel, Avaya, Cisco, Mitel and NEC will let users launch and answer PBX-based and IP PBX phone calls and view phone-presence information from the Office Communicator client. The same client will let users switch between instant messaging and voice sessions. Microsoft also reiterated similar integration projects that are now available from Nortel and Siemens.

Microsoft plans to release the next version of its Office Communicator client later this year with Office 2007. The client features include enhanced voice and video, but also focus on telephony integration.