Abstract: A subscriber television set terminal is linked to a distribution station receiving M television channels in a videocommunication network. The distribution station comprises as many individual channel selectors as there are television channels. A television channel is selected from a terminal by a digital video switching matrix that, for each channel address transmitted in a backward line of a terminal connecting line, connects the addressed channel selector to a forward line in the connecting line.

Abstract: This invention relates to an arrangement for transmitting a digital supplementary information signal having a low rate with a digital data signal having a high rate. The insertion of the supplementary information in the data signal is based on the modification of the accumulative disparity of data signal as a function of the logic level of the supplementary information signal. According to a first embodiment, parity check words are periodically inserted in the data signal and have their accumulative disparity which depends upon the comparison of the desired parity indicated by the logic level of the supplementary information signal with the accumulative disparity of data digits between two successive parity check words.

Abstract: Monitoring system for a forward and backward link equipped with two way repeaters-regenerators comprises a monitoring station including means for transmitting through the forward link information data and a low frequency control signal and for receiving through said backward link information data and supervisory words respectively monitoring the performance of the repeaters-regenerators and identifying errors made therein. In each repeater regenerator a supervisory word is stored in a shift register and advance pulses for said shift register are obtained by frequency division of the low frequency control signal. The supervisory word is completed by a start bit and a stop bit, and modulates the low frequency control signal. The modulated start stop supervisory word is transmitted to the monitoring station through the backward link.

Abstract: A digital multiplexing and demultiplexing system for time division multiplexing a number of incoming plesiosynchronous low rate component signals and a number of incoming plesiosynchronous intermediate rate component signals into an outgoing single high rate signal. A first multiplexing stage time stores and stuffs the low rate component signals and multiplexes them into synchronous intermediate rate signals. A second multiplexing stage stores and stuffs the plesiosynchronous and synchronous intermediate rate signals and multiplexes them into the outgoing high rate signal.

Abstract: A remote locating system for remote locating the pairs of regenerative repeaters of a bidirectional data transmission line which is interconnected between a monotoring station and a monitored station. The monitoring station comprises a first low frequency generator which generates a first low frequency signal on the forward line channel which is continuously transmitted in the forward direction from the monitoring station to the monotored station in response to the fault detection on the line and a second low frequency generator which generates a second low frequency signal on the backward line channel which is transmitted in the forward direction after the transmission beginning of the first signal. The second signal is modulated by successive pulses, each of which identifies a regenerative repeater pair.

Abstract: In a time-division digital transmission system comprising transmitting and receiving stations interconnected by transmission lines, a number of component digital channels having a low flow rate are multiplexed into a single resultant channel having a high flow rate. The code used in the stations is a binary code and the code used in the lines is a multi-level code such that a number N of bits in the binary code corresponds to a smaller number N' of digits of the multi-level code. Consequently, a predetermined flow rate in the stations corresponds to a smaller flow rate in the lines, equal to N'/N times the flow rate in the stations.

Abstract: In the field of digital data multiplexing systems, the master rates assigned to the different channels are defined by the national Telecommunications Authorities. It may and actually does happen that the master rates differ in different countries. A direct bit per bit multiplexing system from a first low master rate to a second high master rate is proposed which allows demultiplexing the high-rate digital signal into intermediate-rate signals. The number of the synchro and stuffing bits in the high-rate signal and intermediate-rate signals being known, only the low-rate signals are stuffed in dependence upon the difference between their own timing and the local timing at the multiplexing station.