A method and apparatus is provided for identifying ports on a power distribution board. In one aspect, the power distribution board is configured to output a plurality of signals from a plurality of ports, so that each of the output signals is different with respect to at least one signal characteristic from the other signals. In another aspect a table is provided that relates port identifiers to values of the signal characteristic. A server measures the value of the signal characteristic for a signal that is fed to the server by the power distribution board and identifies the port that outputs the signal by consulting the table.