As one example, a fuel rail assembly for supplying pressurized fuel to a plurality of cylinders of an engine is provided. The portable object, in particular a wristwatch, includes a memory, several positions of which for access words are kept secret by a read andor write barrier and at least one position of which for a word is readable. The system also includes an actuation mechanism that creates a relative displacement between the cooling fan and the chassis when a control signal is applied to the actuation mechanism. The ultrasound signal may be encoded with information on the compliance zone.