In a local module (11(1)) of an asynchronous time division exchange or switching system, each of connection ports (17) transfers a transmission signal to a module bus (19) as a cell with its header made to indicate a destination module number and a destination port number as a VCI (Virtual channel identifier)...http://www.google.de/patents/US5287355?utm_source=gb-gplus-sharePatent US5287355 - Module comprising in an ATM exchange connection ports, each transmitting a cell indicative of a destination module in a cell header
