RingCentral MVP is a cloud business phone system that ... If you were to develop a PBX system using the Asterisk framework and have never used it before, you can access plenty of documentation ...

Open source PBX software that runs under Linux and other ... Supporting traditional telephony (TDM) as well as voice over IP (VoIP), Asterisk is written in C and uses the Unix standard POSIX ...

A VoIP-based PBX system that is hosted by a service provider over the Internet. All phone features such as auto attendant, voicemail and conference calling are handled in the cloud PBX datacenter.