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
MCK communication is a part of Citel technologies, The VoIP Migration Company. MCK products like EXTenders, Gateways, and DTI call center solutions, are now available through Citel.