Essentially, a system of Communications allows to transmit and/or to receive information. The components and the characteristics of the system determine what type of information it can be transmitted or received, how many channels, in what frequencies, with what speed and fidelity, to what cost and with what covering, besides their grade of immunity in front of noise and interferences and to other operation parameters. The system of communication of data through the domiciliary electric net this constituted by two types of elements: physical and logical; their design and construction involves the electronics, the electricity and the computer science; the speed of the data is limited by the width of band of the bifilar line and for the code techniques and used modulation; the transmission frequencies are selected according to the norm CENELEC EN50065-1, the covering is local domiciliary, the immunity in front of noise and interferences depends on the transmission frequency and of the use of a transmission type to two threads: line-earth or line-neuter; as for costs, the system is an economic alternative and of quick installation for the transport of data.