A method of estimating a noise present on a 2-wire line connected to a modem using a plurality of frequency bands is implemented by a noise estimation device connected to the 2-wire line. The method comprises obtaining a first voltage value of a differential mode voltage at the two wires of the secondary side of the differential mode circuit, the first voltage value measured on the plurality of frequency bands and a second voltage value of a common mode image voltage corresponding to a voltage at the two wires of the secondary side of the common mode circuit, resulting from said differential mode voltage, the second voltage value being measured on the plurality of frequency bands and transmitting the first voltage value and the second voltage value to a calculating module configured to provide a noise estimate based on the first and second voltage values.