An attachment rack apparatus with antenna is provided, including a first connection unit, a second connection unit and an antenna unit. A computer attached to the transducer determines when each consumption point is active and measures the respective amount of fluid drawn by each. A power line for data retention for power shutdown is formed with wirings finer than a usual main power line. The additional resistors may be selectively connected by means of switches disposed between the output of the voltage generator and a respective intermediate node so as to define an output voltage V0 programmable on the basis of command signals supplied to the switches.