This Technical report (type 3) summarizes the results obtained through an intense activity of research carried out in some European countries, in order to assess the ability of MV (medium voltage) and LV (low voltage) distribution power networks to be used as a data transmission medium suitable to support applications related to distribution automation systems. Taking into account that the research has been focused on a reduced number of typical situations, the results, shown in this report, will be considered representative of all the situations similar to those that have been investigated. The results are expressed with reference to certain transmission parameters, described in clause 2, which are of great importance for the design of a distribution line carrier communication system.