Asterisk is a telephone private branch exchange (PBX), created in 1999 as open software for Linux and other UNIX-like systems.
Like other private branch exchanges, it allows attached telephones to make calls to one another and provides connections to outside lines to make and receive calls. To Asterisk, a VoIP provider represents a means to obtain a direct inward dialable number to receive calls and a trunk for outbound calls.
Asterisk is at the heart of various products, such as PBX in a Flash and Trixbox, intended to join multiple individual telephone extensions or devices as one office-style system. There are even versions of Asterisk which run under OpenWRT, an embedded Linux which was installable on some Linux-based Linksys routers.
There are two standard methods to connect an Asterisk box to icttech.net:
- Asterisk (IAX2), to use the Inter-Asterisk protocol
- Asterisk (SIP), to use the same standard Session Initiation Protocol used to connect to SIP phones
- Asterisk (PJSIP), to use the Open Source Embedded SIP protocol stack
Asterisk is complex but powerful; complete information on its deployment and use would fill a book. See: