NEW YORK — Six months after announcing a grand VoIP-focused partnership that was light on specifics, Microsoft and Nortel this week detailed a series of planned products, including branch-office gear and offerings that address security and multimedia needs

Speaking from the stage that hosts “Saturday Night Live,” Microsoft CEO Steve Ballmer and Nortel CEO Mike Zafirovski updated 100 or so customers, as well as analysts and press, on their four-year Innovative Communications Alliance. The effort, which should give customers an alternative to offerings from Avaya, Cisco, Siemens and others, involves sharing intellectual property, research and development, support, services and sales personnel.

 The alliance should begin bearing fruit later this month, when the companies plan to ship a branch-office appliance called the United Communications Integrated Branch, which will package Nortel routing and firewall and IP PBX functions with Microsoft’s Office Communicator Server (OCS) 2007, a presence, instant messaging and collaboration software.

Also planned this year is full SIP compatibility between Exchange Server 2007 Unified Communication server (an e-mail platform with presence and IM) and Nortel’s Communication Server 1000 (the company’s IP PBX).

In addition, the companies are combining Nortel Multimedia Conferencing — a server product that sets up voice and videoconferencing — with Microsoft OCS.

Ballmer said this first phase of integration will involve tying together VoIP and messaging servers from the two companies.

“First, you’ll get smart unified clients,” which link Microsoft messaging, Nortel soft-phone and hard-phone technology, Ballmer said. “After that, we’ll deliver a transformed back end.” Over the next two to three years, customers “can expect to go from a separate PBX and separate server software [environments], to one where [OCS] . . . and Nortel [VoIP] servers deliver the full telephony experience, with both platforms running on standard Intel architecture with common Windows software, development and management tools.”

Nortel also said it would scale up its enterprise IP PBX platform in the second half of this year, with a CS 2000 series that boosts the number of users per system to 200,000 from 10,000 with today’s CS 1000 models.