Abstract: A video conferencing network includes remote video terminals (10) interconnected to a switching network (66) through coaxial cables (16). The switching network (66) is operable to provide an audio and video data path between two or more video terminals (10). The switching network (66) operates as both an audio/video crosspoint switch and also as a network controller. In the network control mode, the switching network (66) operates in both a master mode for maintaining data communication with all of the video terminals (10) and also in a slave mode for maintaining status of devices attached to the switching network (66). In the master mode, the switching network (66) receives requests from each of the video terminals (10) and services these requests to determine available data paths for interconnection with other video terminals. In the slave mode, the switch (66) is in data communication with all of the video terminals (10) to determine the status thereof which is stored in a slave status table.

Abstract: An audio conferencing system includes a plurality of remote stations (10) which are interconnected in a conference mode through a central switching network (66) through communication lines (16). Each of the remote stations has a microphone (34) and a speaker (64) associated therewith. The microphone (34) on each of the remote stations has a voltage controlled amplifier (VCA) (59) associated therewith and the speaker (64) has a VCA (60) associated therewith. A CPU (48) selectively controls the output of the microphone (34) to selectively decrease the gain thereof when voice is not detected. When voice is detected above a predetermined threshold, the microphone (34) is allowed to operate at full gain and the speaker (64) has the output level thereof decreased. This effectively reduces the audio loop gain between remote stations in a conference.