In a computer video conferencing system it is often necessary to transmit multiple channels of information between remote computers, such as a video channel, an audio channel and data sharing channel. A socket based transport interface can be utilized to establish communication channels between...http://www.google.com.hk/patents/US5674003?utm_source=gb-gplus-share專利 US5674003 - Mechanisms for accessing unique features of telephony networks from a protocol-Independent data transport interface 
