DDU: The Front End Driver system (FED) of the CMS drift-tube detector

The DDU board (Detector Dependent Unit, also called DT FED) is part of the Read-Out system of the CMS Drift-Tube detector. It merges data coming from the front-end electronics, in order to build an event fragment and send it to the global CMS DAQ through a S-LINK64 output. The DDU board also receives synchronization commands from the TTC system (Timing, Trigger and Control system), performs error detection on data and sends a fast feedback to the trigger system through the TTS output (Trigger Throttling System). The complete functionality of the DDU has been validated in laboratory and in the Cosmic Challenge exercise performed during summer 2006.