Cisco Unified Call Manager software is the call-processing component of the Cisco Unified Communications system. It is a scalable, distributable, & highly available enterprise IP telephony call-processing solution. Cisco Unified Call Manager extends enterprise telephony features & capabilities to packet telephony network devices such as IP phones, media processing devices, voice over IP (Vo IP) gateways, & multimedia applications. Additional services such as unified messaging, multimedia conferencing, collaborative contact centers, & interactive multimedia response systems are made possible through Cisco Unified Call Manager open telephony APIs.