Fonality takes a different approach with PBXtra, which, like cousin Trixbox and Critical Links' EdgeBox, incorporates the open source Asterisk. PBXtra is not only the most affordable system in this roundup, but is unique in being a managed product. Customers get a low-end Celeron tower PC that's set up without incurring any installation costs, and a Web interface that lets users customize the system (such as recording voice prompts) without IT help. Fonality remotely monitors the system, provisions the phones, and backs up data off-site.

The PBXtra Professional configuration that I tested hooked up much like other solutions. One big difference (to ensure a good experience) is that Fonality insists on a phone session with an engineer who walks you through the process. With my virtual sidekick along for moral support, I connected the Dell hardware to my network, attached PSTN lines, assigned the server an IP address, and plugged in the supplied Aastra 9112 VoIP phones to my network hub.

The only problem I had was a slight echo on calls over my analog line. This turned out to be a golden opportunity for Fonality to flaunt its remote administration, because my assigned engineer was able to quickly eliminate the problem by adjusting some server settings.

A few clicks on the Web Control Panel (which runs from Fonality's main server) let me fine-tune my PBX setup, including configuring the actions of the auto attendant and recording personalized greetings.

Fonality works with many other inexpensive VoIP phones from Cisco, Polycom, Aastra, Swissvoice, and Snom. Even if you use analog phones, essential features are available, such as a stutter tone to indicate voice mail waiting.

The basic PBXtra features are substantial. These include 600 hours of voice mail (converted to e-mail), call routing rules, auto attendant, and name directory, which should be enough for many small organizations. In addition, every PBXtra configuration supports branch offices. This means you can purchase this economical system for different locations and get free office-to-office calling over VoIP. Additionally, users may forward calls to any extension in the PBXtra server network.

The just-released Version 4.0 software proved superior to other solutions in multiple ways. Foremost, I feel the tabbed Web interface (which is carried forward from the previous release) is the best of the products tested. Features are logically grouped and clearly explained, which makes changes easy for employees. For example, on your personal Web control panel, under the Features tab, you'll find Call Forwarding options. Here you can define how the system processes calls, including following you during certain hours. I found the new scheduler made it very easy to define different messages and then have them play depending on the time of day, and to route calls based on rules. PBXtra accommodates both simple and complex call sequences, allowing you to customize the system for a variety of situations.