The KT670 broadcast communication system for mines is, based on the VoIP technology and standard SIP protocol, used for underground emergency broadcasts and voice calls. It is mainly composed of the broadcast system software and server, broadcast substation, etc. Main functions of the system include the triggered broadcast, instant broadcast, scheduled broadcast, voice broadcast, music broadcast, text broadcast and record broadcast. This system supports multicast and unicast modes. Due to the built-in dynamic multicast technology, the system supports the broadcast priority. In addition to broadcasts, the system also supports IP calls for voice communication between the broadcast substations as well as between the broadcast substation and dispatching center.