A method to automatically remove a crosstalk between a very-high-bit-rate digital subscriber line, VDSL, and a transmission line on a bundle of wires, wherein the transmission line is a G.fast system, the transmission line transmits a signal using a plurality of subcarriers, and the plurality of subcarriers include a first subcarrier having a minimum frequency, comprising: a) obtaining a plurality of loop diagnostic metric data related to a communication loop connected between a distribution point unit, DPU/digital subscriber line access multiplexer, DSLAM, equipment (101, 200) and a customer premises equipment, CPE, wherein the DPU and the CPE are G.fast nodes; b) setting a start point for scanning the loop diagnostic metric data, wherein the start point has a start scan index corresponding to a second subcarrier having a frequency being a sum of a maximum VDSL frequency causing the crosstalk and a guard band; c) scanning at a plurality of scan points from the start point down to a stop point having a stop scan index corresponding to the first subcarrier, wherein the plurality of scan points including the start point and the stop point have a plurality of scan indexes including the start scan index and the stop scan index and corresponding to the plurality of subcarriers including the first and the second subcarriers; and c1) when a specific one of the loop diagnostic metric data complies with a degradation criterion of communication data flow quality, determining a start frequency of the communication loop in the transmission line based on a specific one of the scan indexes and stopping the scanning step, c2) wherein the degradation criterion of communication data flow quality is established based on a sudden degradation resulting in at least one of a non-sustained link and a packet loss in a specific subcarrier having the specific scan index when the difference between a specific one of the loop diagnostic metric data and a datum of a specific graph point on a loop diagnostic metric simulation graph obtained in an absence of the VDSL is greater than a minimum difference. a) obtaining a plurality of loop diagnostic metric data related to a communication loop connected between a distribution point unit, DPU/digital subscriber line access multiplexer, DSLAM, equipment (101, 200) and a customer premises equipment, CPE, wherein the DPU and the CPE are G.fast nodes; b) setting a start point for scanning the loop diagnostic metric data, wherein the start point has a start scan index corresponding to a second subcarrier having a frequency being a sum of a maximum VDSL frequency causing the crosstalk and a guard band; c) scanning at a plurality of scan points from the start point down to a stop point having a stop scan index corresponding to the first subcarrier, c1) when a specific one of the loop diagnostic metric data complies with a degradation criterion of communication data flow quality, determining a start frequency of the communication loop in the transmission line based on a specific one of the scan indexes and stopping the scanning step, c2) wherein the degradation criterion of communication data flow quality is established based on a sudden degradation resulting in at least one of a non-sustained link and a packet loss in a specific subcarrier having the specific scan index when the difference between a specific one of the loop diagnostic metric data and a datum of a specific graph point on a loop diagnostic metric simulation graph obtained in an absence of the VDSL is greater than a minimum difference.