The Asterisk ecosystem has improved significantly in 2006, with a wide range of tools, modules and utilities coming to light that improve the open-source PBX's usability and manageability.

Trixbox, previously known as Asterisk@Home, represents the ultimate Asterisk starter's kit, bundling many of these applications and a full operating system with the underlying PBX software.

While the full distribution, which can be downloaded from www.trixbox.org, greatly simplifies and empowers the Asterisk experience for the uninitiated, its lack of support for mission-critical deployments makes Digium's Asterisk for Business and Four Loop Technologies' Asterisk-based appliances that much more appealing.

One of the advantages of building a PBX from scratch is that you can size the server as needed for your deployment.

Our test system—with its AMD Athlon 64 3500+ processor, 1GB of RAM and 120GB hard disk—left plenty of room for growth.

We downloaded the Trixbox 1.1 installation package in an ISO file that included CentOS Linux 4.3, Asterisk and several telephony applications that enhance Asterisk's ease of use and management.

Users also can download a VMware image to take the Trixbox software for a spin in a virtual machine.

After installing the Trixbox software, we ran the included update script to get the most recent Trixbox version, 1.1.1.

Among other things, the update script automatically executed a yum command to update to the most recent package versions in the CentOS and Trixbox yum repositories.

Among the packages that were installed was the latest CentOS kernel, which has the unfortunate side effect of breaking Asterisk's Zaptel (Zapata Telephony) module.

The Zaptel module handled our analog and digital trunks, and losing the module effectively cut the Trixbox server off from the PSTN (Public Switched Telephone Network).

And therein lies the problem with a roll-your-own PBX solution—there's nowhere to turn in a crisis.

We were able to download the Zaptel source and recompile it, but such actions require a degree of comfort and familiarity with Linux and telephony terms that many small-business administrators may be lacking.

—Andrew Garcia

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