Most modern PBX's will be SIP compliant, that makes them freespeech compatible.
All modern PBX have native VOIP support or can be extended to support a VOIP trunk with additional hardware. Our service is SIP compliant, which is the mostly widely used VOIP standard, and will integrate easily with most PBX's (ask your PBX supplier). Asterisk, the most popular 'free' PBX, is easy to configure with a freespeech trunk.
Adding a freespeech line to your PBX can provide you with low cost call routing and has the benefit of handling simultaneous calls so you can have as many calls running as your broadband bandwidth supports, without having to invest in costly ISDN lines. You can also benefit from adding extra numbers for inbound calls.
The option PBX connect is ideal for those who route large volumes of voice traffic. See full list of call rates for PBX connect