Name : Osvaldo Catalano E-mail : catalano@ifcai.pa.cnr.it Institute : Istituto di Fisica Cosmica con Applicazioni all'Informatica - CNR , Palermo, Italy TITLE : EUSO System Electronics ABSTRACT : EUSO (Extreme Universe Space Observatory) has been selected by the ESA (European Space Agency) as a mission to be accommodated on the Columbus external facilities module of the ISS (International Space Station). EUSO, currently in phase A study, is scheduled to be launched by the end of 2007. The system electronics acting as the "brain" of the EUSO telescope is described in the paper. The front-end, read-out, on board data handling and trigger electronics specifically designed for the experiment are presented. The solutions adopted have been introduced to maximize the signal-to-noise ratio and minimize the requirements for power consumption, weight and volume. The characteristic faint fluorescence signals seen by the telescope from an altitude of 400 km, averaged altitude of the ISS, are taken into account to study the response function of the EUSO instrument.