The Cisco MCS 7845-I2 Unified Communications Manager Appliance is a high-availability server platform for Cisco Unified Communications Manager 6.0 or 5.1 and an integral part of a complete, scalable architecture for a new generation of high-quality unified communications solutions for enterprise data networks. It delivers the high performance and availability that today's enterprise networks demand-and is easy to deploy and highly cost-effective. The server appliance is preinstalled with an operating system and Cisco Unified Communications Manager 6.0 or 5.1. Cisco Unified Communications Manager was formerly known as Cisco Unified CallManager. It is fully operational upon startup, requiring entry of just a few configuration items such as IP address and domain. At just 2 rack units (2RU) high, the Cisco MCS 7845-I2 Unified Communications Manager Appliance offers tremendous power in a low profile chassis that minimizes rack space. The appliance supports up to 7500 Cisco Unified IP phones per appliance and 30,000 Cisco Unified IP phones per cluster.