The present invention provides methods and related devices for adjusting the passband and/or cutoff frequency of a high-pass filter of an ADSL modem. A level of a received ADSL signal is compared with a predetermined signal level to provide a comparison result. A control signal is generated based on the comparison result and the passband and/or the cutoff frequency of the high-pass filter is adjusted responsive to the control signal. Devices and computer program products are also provided.