Abstract: For the preparation of data such as digitized television channel signals or television channel bundles, useful data are periodically replaced by a frame marker (F) in at least one of N parallel partial data streams of different bit significance. For this replacement, a partial data stream of low bit significance is selected because there the degradation is lowest. Because of this measure, the bit rate does not have to be increased in order to include a frame marker and a simple structure is possible for the multiplexer and demultiplexer at the respective transmission interfaces.

Abstract: A service integrated transmission system for transmitting, over a light transmission path, digital signals having a transmission band whose upper limit frequency corresponds to the maximum bit rate of the signals to be transmitted, the transmission being effected by simultaneously transmitting, over the transmission path, digital signals having a high bit rate only in an upper part of the transmission band and digital signals having a low bit rate only in a lower part of the transmission band. The system includes a transmitter at one end of the path which separately multiplexes low bit rate signals into a narrowband signal and high bit rate signals into a broadband signal, combines those multiplexed signals, and modulates a light source with the combined signal. A receiver at the other end of the path converts the modulated light signal into a demodulated electrical signal, separates the two multiplexed signals, and then demultiplexes each of the latter signals.

Abstract: A terminal device for use in a service integrated, multiplex digital signal transmission system which includes an optical fiber waveguide line connected to the terminal for conducting a light signal and a member for modulating the light signal with multiplexed narrowband signals and multiplexed broadband signals, the terminal device including narrowband signal processing devices connected to the optical fiber waveguide line for transforming only narrowband signals between a multiplexed state and a demultiplexed state, broadband signal processing devices connected to the optical fiber waveguide line for transforming only broadband signals between a multiplexed state and a demultiplexed state, a member connected for normally supplying operating power to said signal processing means from local utility mains, a charge accumulator for supplying operating power in the event of interruption of the power supply by the local mains, and elements connected for switching the terminal device to effect signal transmission