How to Choose Open-Source Telephony

When companies face the task of moving from their old phone systems to IP telephony, they also find themselves faced with deciding whether to choose a proprietary IP phone system or one that's an open-source solution. Knowledge Center contributor David Mandelstam talks about how to make the choice.

By: David Mandelstam


Open-source telephony is a system supporting all types of telephony applications such as PBXes, call centers, interactive voice response systems, chat lines and many other types of voice technologies. They are all based on universally available, free and open-source telephony software such as the Asterisk project. OST runs on standard PC servers rather than proprietary boxes. The only nonstandard components are telephony boards that are used to connect to the standard PSTN (Public Switched Telephone Network).

OST has matured from a hobbyist's toy to a stable, full-featured enterprise-level tool over the past few years. The improvements have been driven by customer experience and demands, and the availability of high-reliability telephony hardware that is compatible with the entire range of motherboards.

There is a significant cost advantage to using OST on generic hardware as opposed to proprietary systems. You get the advantage of a low-cost central PBX (roughly a 70 percent cost saving), plus the ability to shop in the open market for nonproprietary phones, which saves even more. Surprisingly, for most users, ongoing support costs for the system are also lower, due to the fact that OST is supported by people with very generic skills.

The biggest payoff in OST versus proprietary hardware is not the cost savings but the power and feature sets that only the OST offerings present. Because the voice and call control streams are manipulated by ordinary PC software that can be easily modified, extraordinary power is readily available to perform unified messaging. For example, Caller ID incoming calls can be extracted and fed to online databases in real time to harvest information that can be automatically fed to a CRM (customer relationship management) system. So, for instance, before a real estate agent answers an incoming call, her CRM database can already be populated with the customer information including the caller's name and address, credit rating and other demographic information.

OST can also give you almost unlimited control of your telephony and unified communications universe and save a lot of money to boot. But, as always, there are pitfalls of which to be aware.