Asterisk
From New Zealand VoIP Users Group
Contents |
What Is Asterisk
Asterisk® is a complete IP PBX in software. It runs on a wide variety of operating systems including Linux, Mac OS X, OpenBSD, FreeBSD and Sun Solaris and provides all of the features you would expect from a [PBX] including many advanced features that are often associated with high end (and high cost) proprietary [PBX]s. Asterisk's architecture is designed for maximum flexibility and supports Voice over IP in many protocols, and can interoperate with almost all standards-based telephony equipment using relatively inexpensive hardware.
Asterisk® is released as open source under the GNU General Public License (GPL), meaning that it is available for download free of charge. Asterisk® is the most popular open source software available, with the Asterisk Community being the top influencer in VoIP.
Supported platforms
Asterisk® is primarily developed on GNU/Linux for x/86 and runs on GNU/Linux for PPC along with OpenBSD, FreeBSD, and Mac OS X. Other platforms and standards-based UNIX-like operating systems should be reasonably easy to port for anyone with the time and requisite skill to do so.
Asterisk® is available in Debian Stable and is maintained by the Debian VoIP Team.
Supported Hardware
Asterisk® needs no additional hardware for Voice over IP. For interconnection with digital and analog telephony equipment, Asterisk® supports a number of hardware devices, most notably all of the hardware manufactured by Digium®, the creator of Asterisk®.
Features
Asterisk-based telephony solutions offer a rich and flexible feature set. Asterisk® offers both classical PBX functionality and advanced features which interoperates with traditional standards-based telephony systems and Voice over IP systems.
Supported protocols
Asterisk® supports a wide range of protocols for the handling and transmission of voice over traditional telephony interfaces including H.323, Session Initiation Protocol (SIP), Media Gateway Control Protocol (MGCP), and Skinny Client Control Protocol (SCCP).
Using the Inter-Asterisk eXchange (IAX™) Voice over IP protocol Asterisk® merges voice and data traffic seamlessly across disparate networks. The use of Packet Voice allows Asterisk® to send data such as URL information and images in-line with voice traffic, allowing advanced integration of information.
Asterisk® provides a central switching core, with four APIs for modular loading of telephony applications, hardware interfaces, file format handling, and codecs. It allows for transparent switching between all supported interfaces, allowing it to tie together a diverse mixture of telephony systems into a single switching network.
Dialplan
The heart of Asterisk is the dialplan, which tells Asterisk how to handle all of it's calls. Because Asterisk is an open system you are free to adjust the dialplan to your hearts content, something you can only dream about with a proprietary phone system.
Asterisk is very good at integrating VOIP and PSTN phone networks.
Features
- Three way calling
- Conferencing
- Direct in dial (DID)
- Advanced Trunking
- Call recording
- Call detail records (CDR)
- Voicemail
- Interactive voice response (IVR)
- Voice over IP (VOIP)
- Fax detection
- Many, many more.
For a complete feature list see the Asterisk website
