This is a Voice over Internet Protocol (VoIP) and streaming media service based on the Session Initiation Protocol (SIP) by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers equipped with SIP-based private branch exchange (IP-PBX) and Unified Communications facilities
Offers connections ranging from capability for a couple of simultaneous calls for small PBX-equipped businesses to an unlimited number of channels for larger businesses.