Unified Communications or UC is ruled by the Cisco,Microsoft and Avaya. All three companies are developers of great UC software suites but come in at prices that may be out of range for small and medium sized companies. Now i am huge proponent of cutting costs when possible and as such my advice to small companies is to evaluate Open Source UC tools when looking for a new solution to replace your PBX systems.
The state of affairs in the Open Unified Communications market is as follows. The most popular Open Source UC package would be asterisk but it also a little harder to manage than alternative packages. For a small shop with less than 100 phones my recommendation would be Fonality’s Trixbox. Trixbox has a commercial and community edition which is backed by a large user base. Trixbox’s major drawback is its inability to scale for large installs but this is not an issue for a small company.
The best Open Source UC package for Small and Medium size companies is sipXecs. SIPX is totally sip based and was built to scale up to 1000 users. Unlike asterisks which switches voice streams and was built to sit between endpoints, SIPX functions as a sip proxy and does not require endpoints to pass voice data through the SIPX server, it is this fact that allows SIPX to scale better than asterisks.While not as extensible as asterisks SIPX represents a great option for medium sized companies looking to jump into the UC world and at this moments represents the top of the open source UC pile.