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
CallTower`s hosted IP telephony services offering encompasses calling and connectivity; next-generation unified messaging; advanced applications; network services; and software, hardware and management services.
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