The CDF Run II data acquisition is implemented in the industrial VME standard. Front End crates therefore send their data over data links to VME Readout Buffers, VRBs. Scanner CPUs, SCPUs, readout the events and send them over the ATM Event-Builder switch to the Level-3 PC-Farm, where the event is for the first time available in one piece.
In the Level-3 farm the events are received in the converter node. From the converter node the event is shipped to the processor nodes where trigger algorithms are run which decide whether or not to accept the event. An accepted event is then over the output node propagated versus the Consumer Server and Data Logger.