A PLC modem (131-133) is prompted to increase, starting from a predetermined minimum transmit power, a transmit power of data transmission on a PLC channel (112) at a given time or time period defined with respect to a mutual time reference of a DSL channel (111) and the PLC channel (112). A DSL modem (121) is prompted to measure a signal-to-noise value at the given time or time period defined with respect to the mutual time reference. Mitigation of interference 190 between the PLC channel (112) and the DSL channel (111) becomes possible.