A communications system interconnects a number of asynchronous data processing terminals, operating at different speeds among themselves, with a high speed switching or communication network. The system uses as a time multiplexed loop linking terminals which are later duplicated for security reasons....http://www.google.com.hk/patents/US4413338?utm_source=gb-gplus-share專利 US4413338 - Communication system for interconnecting a plurality of asynchronous data processing terminals
