Abstract: One or more pieces of equipment of a hybrid fiber-coaxial (HFC) network has a frequency agile transponder connected thereto. Each frequency agile transponder includes a transmitter (T) and a receiver (R) which are connectable to a coaxial line of the HFC network. Bidirectional communications can occur between a controller and each frequency agile transponder via the HFC network. The frequency agile transponder has analog inputs/outputs connectable to test points of the one or more pieces of equipment of the HFC network. The frequency agile transponder can test the test points and supply to the controller the results of the test. The transmit and receive center frequencies of the transmitter and receiver of the frequency agile transponder can be selectively and remotely adjusted by the controller to avoid signals at carrier frequencies utilized to transmit program material, data signals and/or telephony signals.