AGI allows admins to write plug-ins for Asterisk in just about any language, including Python, PHP, Ruby, Java, C, and Perl. As such, customizing your PBX’s feature set is relatively easy, and with the community of developers designing tools for Asterisk growing rapidly, ready-made features abound. Examples include a trouble-ticket management app that accepts ticket number input from a dial pad and another that performs an Amazon lookup of keyed-in 10-digit ISBN numbers and recites book prices back to the caller.

Open for experimentation
The phone system may very well remain the most commonly used and relied-on corporate app. Interaction with the phone system is constant, and the features, performance, and stability of the system are under constant subconscious scrutiny. Voice mail features and ease of use, voice mail/e-mail gateways, call quality, and follow-me features are all highly visible components of any PBX, to users on both sides of the dial tone, and IVR functions and reliability can make or break sales and business relationships. As such, commitment to an IP PBX should by no means be taken lightly — especially when it comes to assessing how well a VoIP solution will adapt to future evolutions in your enterprise.

As with all open source solutions, the beauty of Asterisk is that it allows you to try before you buy. What’s more, Asterisk is available in a dozen different forms, via packaged solutions such as Trixbox and AsteriskNOW or as raw source code. Trixbox and AsteriskNOW are also available as prepared VMware images — simply download and boot them on a VMware workstation or server. It couldn’t be easier to set aside your misgivings and investigate the viability of open source VoIP yourself.

Soon enough, as more and more companies become comfortable widening their search beyond commercial fare, they will find that open source dial tone is a worthwhile alternative, in it for the long haul. The cost savings are that compelling, as is the promise of greater customization and control. And as voice penetrates deeper into the enterprise in the years to come, the ability to quickly code customized features could give companies employing open source IP PBXes such as Asterisk a significant leg up in fulfilling the much-discussed promise of VoIP apps.