Abstract: A cable adapter port module (CAPM) for providing test access to communication circuits associated with a digital subscriber line access multiplexer (DSLAM) includes a first plurality of ports for coupling the CAPM to the DSLAM. The CAPM includes a second plurality of ports for coupling the CAPM to a distribution frame (DF). The CAPM includes a selector matrix circuit for switching signals between the DSLAM and the DF. The CAPM includes a controller circuit in communication with the selector matrix circuit for controlling the CAPM. The CAPM receives power signals over a communication link for powering the CAPM. The controller circuit modulates the power signals over the communication link to communicate information signals for testing the communication circuits.