The invention provides a communication system for a power distribution network, which comprises at least two distribution domains, each of the domains includes one management device and at least one electrical device. A pump withdraws a methane product stream from the column. The substituent A and the substituent B include groups different from each other and are bonded to the same or different nitrogen atoms in the molecule. After the refresh of the bank has been completed, the data stored in the SRAM are transferred to the DRAM bank. The two end walls include locking mechanisms for holding the various components of the apparatus together. The transmitting circuit has a circuit for calculating a value of the running parameter based on the signal originating from the sensor, a transmitter connected to the antenna to transmit this value to the receiving device, and an optimization circuit for activating the transmission of the transmitter to moments independent of the changes of state of the sensor.