The invention concerns an active CATV coaxial line tree (CN) which is common to each of a plurality of network termination units (NT/A) on the subscriber side and which is provided with amplifiers and into which TV distribution signals are fed from a CATV head-end. The active CATV coaxial line tree (CN) is supplemented to form a bidirectionally operable subscriber connection network for transmitting digital signals of bidirectional interactive telecommunication services by an optical waveguide network (OB) emerging from a higher-order connection device (CU) or leading thereto, such that the optical waveguides (OB) are each connected bidirectionally downstream of the subscriber-subsequent coaxial line amplifier (V) to the branches of the coaxial line network (CN) leading therefrom to the subscribers (NT/A).