The Session Initiation Protocol (SIP) is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol (IP). wikipedia.org

LAMP ("Linux, Apache, MySQL and PHP") is an acronym for a solution stack of free, open source software, referring to: Linux (operating system), Apache HTTP Server, MySQL (database software) and PHP (or sometimes Perl or Python), principal components to build a viable web server. wikipedia.org

Voice over IP (VoIP, abbreviation of voice over Internet Protocol) commonly refers to the communication protocols, technologies, methodologies, and transmission techniques involved in the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. wikipedia.org

C (pronounced like the letter C) is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. wikipedia.org

An application programming interface (API) is a source code based specification intended to be used as an interface by software components to communicate with each other. An API may include specifications for routines, data structures, object classes, and variables. wikipedia.org

Asterisk is a software implementation of a telephone private branch exchange (PBX). It allows attached telephones to make calls to one another, and to connect to other telephone services including the public switched telephone network (PSTN) and Voice over Internet Protocol (VoIP) services. wikipedia.org

Voice over IP (VoIP, abbreviation of voice over Internet Protocol) commonly refers to the communication protocols, technologies, methodologies, and transmission techniques involved in the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. wikipedia.org

Amazon Web Services (AWS) is a collection of remote computing services (also called web services) that together make up a cloud computing platform, offered over the Internet by Amazon.com. The most central and well-known of these services are Amazon EC2 and Amazon S3. wikipedia.org

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. wikipedia.org

The Kamailio SIP server is a Open Source software for building SIP services such as a SIP proxy, SIP Presence Server, and SIP location server.

MySQL is a relational database management system (RDBMS) that runs as a server providing multi-user access to a number of databases. wikipedia.org

FreePBX is a GUI (graphical user interface) that controls and manages Asterisk, an open source telephony engine software.