Open Source Software PBX – ready for prime time?

I’ve been working with a client who needs to replace an aging PBX but is (as is everyone) extremely cost averse.  What are their options?

A vendor supported PBX plus desktop phone sets together would probably cost them more than $10k.  Obviously a vendor supported system has losts of advantages from a user support standpoint, but the inistial costs are high, as are the maintenace costs.

In researching solutions I came across and open source software PBX that looks like it will fit the bill.  Asterisk (www.asterisk.org) was originally developed by Digium and is published under a GPL.  The software comes in two flavors, a the full version or a quick start version called AsteriskNow.  The software is meant to run on any open sources Unix server, but is recommended to run on Linux.  It can also be run on a Windows machine, but I would expect that to be problematic.  Interestingly, it also has a MAC OS  X build.  It can handle (obviously) VOIP, but can also interface with standard POTS lines.

Asterisk is loaded with featuresthat you would normally find on big, expensive PBX’s.  Standard stuff like call forwarding, voicemail, conferencing, call waiting, music on hold are there, but the real value is in the features that are standard here, but very expensive in vendor systems.  Things like text to speech, SMS messaging, streaming media, conference bridging, automated attendant and unified messaging among many others are all included.  In addition Asterisk can function as a call center, routing calls to available agents based on anything you want.  While this is not something my client needs, it is there, and is an example of how far the open source model can go. 

Asterisk uses a modular architecture so that new technologies can be integrated easily into the system.  The system is broken into four API’s that are seperate from the core PBX functions.  This abstratction allows new modules to be added or removed without affecting the core switching functionality. 

What strikes me about this is not only the avalability of the software, which all by itself is remarkable, but the quality and depth of the feature set.  Yes, this is largely to drive business to Digium, but that’s ok, the software is out there, and the community is growing to support it.  The great thing about the Digium piece is that you can try the implementation youself, and if the support becomes too much to handle, you can contract with them if you need to.  Its a great safety net.