http://www.cisco.com/en/US/solutions/collateral/ns340/ns414/ns728/ns784/716742.pdf

This document describes the simultaneous ring feature interoperability and documents the steps and configurations necessary for Cisco Unified Communications Manager (Cisco UCM) Release 7.0(1) to interoperate with Microsoft Office Communications Server (OCS) 2007 Enterprise Edition. It aims to provide a good understanding of what works and what does not work in terms of the feature interaction between a Cisco UCM device and Microsoft Office Communicator. It also provides guidance to deployment participants regarding the limitations, expected behaviors, and known issues. Please note that this document does not address performance and scalability, which are part of a broader criteria for a deployment-ready solution.