PortAudio is a cross platform, open-source, audio I/O library.It provides a very simple API for recording and/or playing sound using a simple callback function.
mSoftSwitch is a voip soft switch developed by megaNet Global Inc. established in 2006. mSoftSwitch has been providing services to many small to medium sized voip operators for the last 9 years and is known for the high reliability / high customizability
OFX Systems provides a broad range of products and services including superior switching, voice mail, unified messaging and telephone automation devices.