A new version of Asterisk open source VoIP software turns a low-wattage server into a communications server to power IP PBX systems, VoIP gateways, or conference servers.
By J. Trent Leonard
VARs that want to save their SMB clients money on voice service, take note. In October 2010, open source telephony vendor Digium Inc. released the latest rendition of its popular, free VoIP software Asterisk. The new version, 1.8, will be supported for four years.
Asterisk can turn a low-wattage server into a communications server to power IP PBX systems, VoIP gateways, or conference servers. 
The Huntsville, Ala.-based company has packed more than 200 enhancements and updates into the new release. One feature that should make VARs take notice, however, is the software’s native support—including calendar integration—for the Google Voice telecommunications service, as well as Google Talk, Google’s free instant messaging and VoIP client application.
Google Voice has announced that all U.S. and Canadian voice calls will remain free throughout 2011. Google Voice is not a telecom, however, so its service is not a drop-in replacement for a standard VoIP provider—for example, there is no 911 service. But by employing some creative approaches to the challenges presented by the free service, VARs can easily contain costs for their clients.
Since Google Voice accounts are no longer invitation only, getting a local number for each line or person should be a fairly straightforward process. With some simple configurations, each Google Voice number can be assigned to an extension or ring group. An integrated voice response (IVR) module is also built in to native Asterisk, enabling a computer to detect voice and touch tones using a normal phone call and respond with prerecorded or dynamically generated audio.
Several prebuilt Asterisk 1.8 solutions are available, including open source PBX in a Flash software and Trixbox, a hardware/software solution from Culver City, Calif.-based Fonality, which provides an open source version of the solution as well as a commercial, hybrid-hosted offering. Both eschew the command line-only Asterisk software for integration with the open source Web administrative overlay FreePBX, which moves most of the Asterisk configuration work normally done via the command line to a Web interface. By implementing FreePBX along with Asterisk, the configuration learning curve is also reduced.
Some other notable Asterisk 1.8 features include calendar integration via Microsoft Exchange, CalDev, or iCalendar; scalable and efficient handset paging using multicast Real Time Protocol (RTP); up-to-the-microsecond, high-resolution time stamps for call data records; high-definition audio codecs; and more.
Asterisk is licensed under the GNU General Public License (GPLv2), and is freely downloadable.
