What is Asterisk
Asterisk is an open-source telephony engine and toolkit that enables the creation of communication applications. It functions primarily as a Private Branch Exchange (PBX) but can be adapted for many telephony scenarios including VoIP gateways, conference servers, call centers, and voicemail systems.
At its core, Asterisk provides:
Channel abstraction: Unified interface for multiple telephony protocols and hardware.
Dialplan execution: Programmable call routing and logic via the PBX engine.
Media bridging: Connecting and mixing audio/video streams between channels.
Application framework: Extensible set of call handling applications.
Management interfaces: Control and monitoring via AMI, ARI, and CLI.
Details
It conains core components, architectural layers, and how they interact to provide PBX functionality. For detailed information about specific subsystems, refer to the following areas:
Getting Started
Core Architecture
Signaling Protocols
Media and RTP
Applications and Features
Management and Control Interfaces and Network Infrastructure