An exemplary apparatus for use in a cable-based network includes passive circuitry coupled with an input of the apparatus and configured to generate an output signal having frequency response characteristics controlled as a function of a value of at least one component in the passive circuitry. The apparatus further includes active circuitry coupled with the input of the apparatus. The active circuitry is configured to generate a message signal indicative of a presence of the apparatus in the cable-based network in response to an interrogation signal supplied to the apparatus.