An apparatus including: a first port configured to receive a first end of a cable to provide a communication link between (i) the first port, and (ii) a second port coupled to a second end of the cable. The apparatus further includes a processor configured to, during a time that the first end of the cable is coupled to the first port and the second end of the cable is coupled to the second port, (i) receive a command to identify the second port to which the second end of the cable is coupled, and (ii) in response to the command, repeatedly change the state of the communication link at the first port in accordance with a pattern.