Educational December 5, 2025

What is Asterisk PBX? Complete Guide to Open Source VoIP

Everything you need to know about Asterisk, the world's most popular open source PBX. History, features, use cases, and how to get started.

What is Asterisk?

Asterisk is an open source communications platform that turns a standard computer into a powerful telephone system. It can function as a PBX, IVR system, conference server, voicemail server, and more.

Created in 1999 by Mark Spencer at Digium (now part of Sangoma), Asterisk has become the foundation for millions of phone systems worldwide. It powers everything from small office systems to large enterprise deployments and carrier-grade solutions.

Key Point: Asterisk is the engine that powers other PBX systems like FreePBX, Issabel, and VitalPBX. These add user-friendly web interfaces on top of Asterisk.

Brief History

  • 1999: Mark Spencer creates Asterisk at Digium
  • 2004: FreePBX project begins, adding web interface
  • 2010: Asterisk 1.8 LTS released with major improvements
  • 2018: Sangoma acquires Digium
  • 2024: Asterisk 21 LTS - current stable version

Key Features

  • PBX functionality
  • IVR/Auto attendant
  • Voicemail with email
  • Call recording
  • Conference bridges
  • Call queues/ACD
  • SIP trunking support
  • Codec transcoding
  • Custom applications
  • API integrations

Asterisk vs FreePBX

AspectAsteriskFreePBX
What it isTelephony engineWeb GUI for Asterisk
ConfigurationConfig files, CLIWeb interface
Learning curveSteepModerate
FlexibilityMaximumHigh (with modules)
Best forDevelopers, custom appsMost businesses

Recommendation: For most users, start with FreePBX. It uses Asterisk under the hood but provides a much easier management experience.

Common Use Cases

Small Business PBX

Replace expensive proprietary phone systems with a flexible, low-cost solution.

Call Centers

Queue management, agent routing, real-time statistics, and call recording.

IVR Applications

Automated phone menus, surveys, appointment reminders, and more.

VoIP Service Providers

Build your own hosted PBX platform or calling service.

Getting Started

Hardware Requirements

  • Small office (1-10 users): Any modern PC, 2GB RAM
  • Medium (10-50 users): Dedicated server, 4GB RAM, SSD
  • Large (50+ users): Server-grade hardware, 8GB+ RAM

Next Steps

  • 1. Install FreePBX or Asterisk on a VM or dedicated server
  • 2. Get a SIP trunk from IPComms
  • 3. Configure extensions and routing
  • 4. Connect IP phones or softphones

Ready to Connect Asterisk?

IPComms provides SIP trunks optimized for Asterisk and FreePBX. Free test trunks available.

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