A test apparatus for a broadband telecommunication network. The apparatus includes a DC power source having a first electrical terminal and a second electrical terminal and a DC feeding bridge having a pair of inputs coupled to the first and second electrical terminals of the DC power source. The first electrical circuit having at least one circuit section having a transformer-coupled impedance formed by at least one transformer connected in parallel to a first impedance, and a pair of outputs that are adapted for establishing electrical contact with a device under test (DUT) configured to be disposed on a pair of transmission lines of the broadband telecommunication network.