Asterisk Basics

My goal for this page is to give you a general overview of what Asterisk is and how it does its job - basic background material.

Asterisk is very flexible in how it can receive incoming calls and route outbound calls. If you have traditional phone service (POTS or T1/PRI) then your system will require an FXO interface, typically either a Digium or Sangoma card. Home (and possibly small business users) may purchase VoIP service from a provider who can route multiple channels of VoIP traffic over a broadband connection and no special hardware is required beyond your ethernet or USB internet connection.

Asterisk uses a set of plain-text configuration files to manage its connections and behavior. As a new user you'll be most concerned with three of these files:

  • sip.conf - configures SIP channels for both external service providers as well as local softphones and handsets
  • iax.conf - configures IAX channels for both external service providers as well as local softphones and handsets
  • extensions.conf - configures your "dialplan" which controls how calls are answered and routed

Definitions

  • FXO - Foreign Exchange Office: This is where Asterisk answers your incoming lines from your phone provider
  • FXS - Foreign Exchange Station: This is where Asterisk presents a dial-tone to your phone handset
  • IAX - Inter-Asterisk Exchange: A widely supported VoIP standard originally created to allow two Asterisk systems to communicate with each other
  • SIP - Session Initiation Protocol: One of the most common VoIP standard protocols

HowTo/Asterisk/Basics (last edited 2007-03-13 05:07:08 by DanielHallmark)