A packet-switched digital data communication system operable in a store-and-forward mode is provided for enabling substantially simultaneous full-duplex communication between a plurality of telecommunications terminals, facsimile transceivers or other data input sources over a communications network...http://www.google.com.tw/patents/USRE31182?utm_source=gb-gplus-share專利 USRE31182 - Packet-switched data communication system
