This is how we configure outside PSTNaccess or dialing through another SIPtrunk. Beware that this a simplistic example that neglects most security including SRTP First you'll need to be in config mode: Step - 1 Enter Voice Service VOIP security options There are more options but for now we'll just focus on security/allowing connections to and from our phones and the trunk. Router(config)#voice service voip ........

Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........