example methods and system to validate proper network connections between a digital subscriber line access multiplexer and the subscriber loop to a customer location are disclosed . a disclosed example device includes first and second nodes to electrically couple the device to a port of a dslam and to a first end of a communication circuit , the communication circuit to facilitate electrical coupling of the port of the dslam to a central office switch at a second end of the communication circuit , and a signature circuit electrically coupled between the first and second nodes to generate a signature signal in response to a test signal injected onto the communication circuit at a second end of the communication circuit , the signature signal having a magnitude substantially proportional to the test signal .