Asterisk is Linux-based software for creating an easily manageable and feature-rich business communication system. Asterisk includes all the drivers, protocol converters, scripts, codecs, and more needed to perform functions that range from routing and call handling to call recording and generating call detail records.
Asterisk VoIP software is open source and free, with many configuration options, features, and modules. An Asterisk VoIP solution is preferred by businesses — small and large — who want a robust and customizable IP PBX system to handle their business telephony traffic.
Asterisk is a framework for building a communications network, which can include conference servers as well as the basic PBX system Asterisk was originally designed to support. Asterisk uses the most common protocol — session initiated protocol (SIP) — and is built on one of the most stable and advanced operating systems (Linux). This makes Asterisk a reliable and extendable VoIP solution for businesses of all types.
Some of the business and organizations using Asterisk include:
- Small and medium businesses
- Carriers (CLECs, ILECs, and wholesalers)
- ITSPs, ISPs, and VoIP providers
- Government agencies
- Large corporations
- Call centers
- Call shops
Asterisk is powerful, flexible, and stable. Asterisk was named for the * character in Linux, which is a wildcard character. Like its namesake, Asterisk is capable of performing many different functions — singularly or combined. Some of the functionalities of Asterisk VoIP software are:
- VoIP gateway
- IP PBX
- Skype gateway
- Call center automatic call distributor (ACD)
- Conference bridge
- IVR server
- Voicemail system
- Fax server
- Speech server
- Call recorder
- Unified messaging
Asterisk resources such as whitepapers, videos, and forums can be found at asterisk.org, where the software can also be downloaded. As an open source platform, additional resources for Asterisk VoIP software — such as tutorials for integration with OpenSIPS or software for reporting — can be found all over the Internet. Looking for Asterisk software, hardware, tips, tutorials, or forums? We can help — check our Asterisk resources directory.
Building an Asterisk VoIP PBX is relatively simple from an installation standpoint, as long as you are familiar with Linux and comfortable using the command line interface (CLI). Binary installations using Yum on CentOS or RedHat makes Asterisk easier to maintain, according to the software's developers. There are many Asterisk resources offering installation instructions, including the Asterisk website as well as numerous unofficial how-tos.
Once the Asterisk software is set up, additional software — a graphical user interface (GUI), or front-end — is needed to interface with the Asterisk VoIP system to manage and configure standard features such as music-on-hold and voicemail. There are a number of Asterisk GUIs available, such as Mini Asterisk or GEOTEK Phonebook. You can find Asterisk GUIs in our Asterisk resources directory below, and a complete list of Asterisk GUIs at VoIP-Info.org.
However, that might not be the most stress-free process for many. Thankfully, there are also many software packages out there called distros that roll up the open source Asterisk VoIP PBX software and the GUI with additional components and an easy-install executable. AsteriskNOW is the distro offered by Asterisk, which does the heavy lifting by installing Linux, Asterisk, and the GUI as an ISO image, simply and easily. Some of the more popular distros for Asterisk VoIP service include:
- PBX in a Flash
You'll find Asterisk resources like distros for setup, configuring, and customizing the PBX software in our Asterisk resources directory.
One of the easier ways to install the Asterisk VoIP system is to use an Asterisk appliance. Asterisk appliances are small standalone servers and complete PBX solutions for small and medium businesses (SMBs).
Asterisk appliances come fully loaded with custom compiled Linux configurations, FXO and FXS ports, and a front-end (or GUI) to manage and configure Asterisk's features. Some well-known Asterisk appliances are:
- Asterisk Appliance
- Rhino Ceros Appliance
- WARP Appliance
- PhoneBochs MiniVoIP Appliance
Some developers of Asterisk distros also produce Asterisk appliances, so you can find a simple, comprehensive solution to Linux and Asterisk installation issues, the need for a dedicated machine, and the need for a GUI to manage the Asterisk software all in one compact package. Digium's Switchvox and AsteriskNOW as well as Trixbox are just a few of the distros that also come preloaded on Asterisk appliances.
You'll find more Asterisk appliances, GUIs, and other software in our VoIP Asterisk resources directory.
When considering an Asterisk appliance, it's best to weigh a few factors carefully before making a final choice. Even though Asterisk is open source, a Digium Asterisk appliance — Switchvox — offers certain advantages in that it's fully supported and will upgrade at pace with Asterisk. Relying on community maintenance for independent Asterisk appliances can be a more complicated and even risky process.
Things to consider when evaluating an independent Asterisk appliance:
- Extendability and portability
- Compatibility with other programs/interfaces
- Adequate support
- Statistical aggregation ('phoning home' with usage data)
You can find these and more Asterisk appliances in our VoIP Asterisk resources directory, as well as links to tips, reference material, and hardware options.
The official Asterisk site offers a forum, instructional videos, documentation and more. However, there are also plenty of other Asterisk resources available as well, including forums and installation help at AsteriskGuru and courses and certifications at Digium.
There are also sites featuring extensive documentation, such as the online O'Reilly guide to Asterisk, and sites with how-to vodcasts. Local Asterisk user groups are another online Asterisk resource, as are sites with news about Asterisk developments, updates, and releases. You can find links to these online Asterisk resources and more in our directory.
Because Asterisk is open source software, many companies and independent developers offer modules and add-ons for additional PBX features and functions — especially for industry-specific functions relating to call centers or VoIP providers. For instance, software for call center stats, call recording, autodialers, or conference management, as well as channel drivers, scripts, and other tools are all available through third-party agents.
Information about these and other Asterisk resources can be found in our directory.
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