Cisco MCS 7845-I1 Unified CallManager Appliance is a high-availability server platform for Cisco Unified CallManager and an integral part of a complete, scalable architecture for a new generation of high-quality IP 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 CallManager. It is fully operational upon startup, requiring entry of just a few configuration items such as IP address and domain. At just 2 rackunits (2RU) high, the Cisco MCS 7845-I1 offers tremendous power in a low-profile chassis that minimizes rack space. The appliance supports up to 7,500 IP phones per appliance and 30,000 IP phones per cluster.