If you are interested in Voice over IP, are not intimidated by open-source software, and dont want to part with tens of thousands of dollars up front, take a close look at Asterisk (www.asterisk.org). Developed largely by Mark Spencer, this Linux-based, open-source PBX replacement is an excellent appli-cation and can even be considered for use as your permanent VoIP gateway solution.
Asterisk provides most features of traditional PBXs, such as voice mail services, call conferencing, ACD (Automatic Call Distribution), and IVR (Interactive Voice Response), to name just a few. In addition, it can handle call queuing, bridging, and conference calling with the use of virtual conference rooms. With its automatic generation of CDRs (Call Detail Records), the solution also points to Mark Spencers aspirations of having it become a viable alternative to traditional PBX solutions.
Using Asterisk was very satisfactory, and the overall call quality was excellent. What imperfections we experienced in the VoIP calls could be attributed to poor network conditions rather than Asterisk. The systems performance impressed us, especially considering that we had installed it on a 500-MHz Pentium III system with 256MB of RAM. This was fine for our testing purposes, in which we ran a household telephone system with only four phones. But if you are planning to use this in an office environment, youll need to scale your hardware to match your performance needs. CPU utilization will quickly increase when multiple calls are in progress.
One challenge to keep in mind from the beginning: Depending on the hardware you select for your system (especially the phones), you might encounter glitches such as poor sound quality that have to be researched and then patched or fixed. This is a major downside to implementing an open-source solution; it usually does not provide an integrated end-to-end package, including hardware and software. While you have more flexibility in the hardware and software selection, you might find yourself having to solve any number of problems.
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