Asterisk is an Open Source software PBX (Private Branch Exchange), developed by Mark Specer of Digium. It allows you to make calls to one another which may have connected to other PSTN (Public Switched Telephone Network) and Voice over Internet Protocol (VoIP). Asterisk runs on Linux, BSD, MacOSX and others. Having built-in features like voicemail, conferencing, IVR, queuing etc.
In this article, we are going to see a basic installation and working of Asterisk 11 in RHEL 6.4/6.3/6.2/6.1/6.0, CentOS 6.4/6.3/6.2/6.1/6.0, Fedora 18,17,16, Ubuntu 12.10/12.04/11.10, Linux Mint 14/13 and Debian Linux Operating Systems.