Standards of EN 50083 series deal with cable networks for television signals, sound signals and interactive services including equipment, systems and installations -- for headend-reception, processing and distribution of television and sound signals and their associated data signals and -- for processing, interfacing and transmitting all kinds of signals for interactive services using all applicable transmission media. All kinds of network like -- CATV-networks -- MATV-networks and SMATV-networks -- individual receiving networks and all kinds of equipment, systems and installations such as networks, are within this scope. The extent of these standardisation work is from the antennas, special signal source inputs to the headend or other interface points to the network up to the system outlet or the terminal input, where no system outlet exists. The standardisation of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals (etc.) as well as of any coaxial and optical cables and accessories therefor is excluded. Specific scope of this part 10 This standard is dealing with the transparent return path of cable networks operated in the frequency range between 5 MHz and 65 MHz or parts thereof. Higher frequencies may be used in fibre based networks. NOTE - In addition it is possible to use the frequency range from 0 Mhz to 5 MHz for return path transmissions, e.g. for NMS or other control, monitoring and signalling purposes. Applications below 5 MHz are not covered by this standard. An active return path carries typically only return signals. A passive return path can be used for both return and forward signals. This standard lays down the basic methods of measurement for signals typically used in the return path og cable networks in order to assess the performance of those signals and their performance limits.