An electrical cable can create magnetic interference that may affect unshielded telephone cords.

Typically, this is caused by tangled telephone or power cords. Untangle Telephone and Electrical Cords. Please make sure that your electrical cords and telephone cord is not tangled. You may also want to make sure that your phone cord is not exceptionally long or unshielded.

You may want to use a short phone cord that is only long enough to reach the jack and does not coil because of excessive cord slack.