The document describes a multimedia conferencing system called MCS 3.0. It allows for video conferencing over a network between PCs. The system uses a client-server architecture with clients connecting to conference servers. Media links and interchanges are used to route audio and video packets between local area networks. The system supports various video and audio codecs and compression standards to optimize quality and file size. It can be used to enable intercommunication between offices, classrooms, and government agencies over an ATM backbone network.