Asterisk was originally created as the engine for a PBX system (in fact, many refer to it as the Asterisk PBX) and includes all of the components necessary to build a powerful, scalable business phone system. These include advanced features that usually cost extra on a commercial phone system: things like voicemail, automated attendant, call queueing, conference bridging, parking, paging, and intercom calling.
Asterisk is technology and protocol agnostic, which means that you can connect it to the outside world using VoIP or traditional telephony technologies. It also means that you can use virtually any standards-based IP phone; Asterisk includes drivers for SIP and other protocols. That being said, Sangoma offers a line of IP phones that were specifically designed to compliment Asterisk and take advantage of a number of key productivity features.
Asterisk is future-proof. Unlike traditional phone systems that are generally upgraded using a forklift, Asterisk continues to evolve. Phone systems based on Asterisk see significant improvements each year as new features are included.
Build From Scratch
There are several options for building a PBX system using Asterisk. You can build a completely custom solution from scratch, starting with just the raw Asterisk engine. This gives you complete control over the way your phone system operates, but requires a good deal of effort and can be difficult to maintain unless you have an Asterisk expert on staff. Building from scratch is appropriate if you are creating a new product or service, if your project has extremely specific requirements that cannot be met with off-the-shelf solutions, or if you simply enjoy the challenge of learning a new skill.
Build From A Distro
Another DIY option (with a significantly lower learning curve) is to deploy a software appliance like FreePBX. FreePBX is a special Linux distribution that installs the operating system, Asterisk, drivers for telephony cards and IP phones and an open source administrative user interface called FreePBX. The installation process if fully automated and takes roughly 20 minutes to convert a computer into a working phone system.
Buy A Turnkey Solution
Sangoma offers a turnkey PBX system based on Asterisk. The product, called Switchvox, combines the core Asterisk engine with an intuitive user interface and advanced business phone system features like instant messaging, universal inbox and mobility with a softphone. Priced at a fraction of what you would pay for a traditional phone system, Switchvox is the best of both worlds.