Abstract: A data switching node for the simultaneous high speed transmission of data originating from a plurality of source data switching units to a plurality of destination data switching units connected via time bus interface on a looped unidirectional time bus wherein the total information carrying capacity of the node is time multiplexed into separate data channels. Further the time bus interfaces comprise means to vary the number of data channels and their frequency of repetition, to share common channels, to detect between successful and unsuccessful transmissions, to store unsuccessful transmissions for retransmission, to transmit to several destinations at the same time, to monitor load conditions, to detect transmission and other errors on the node and to inform the node controller accordingly.