Abstract: The system allows the implementation of packet-switched synchronous speech communications in the network without requiring any centralized device synchronizing all the network stations. To obtain that, the active periods of each station are subdivided into frames each having a duration equal to the time elapsing between the generation to two subsequent speech packets relating to the same communication; once a station has accessed the line for the speech communications, these communications are allotted time slots which are maintained for the whole communication duration. The slots not allotted to speech communications are allotted to data transmission. The access to the line for a speech communication is obtained by the same contention techniques used also for data transmission.

Abstract: A node in a packet-switching data-transmission network has a processor distributing incoming messages or packets from a receiving buffer to transmitting buffers selected according to routing data established by an updating circuit which algebraically combines incremental delays with respective path delays to obtain total delays assigned to message transmission from the processor over respective transmitting buffers and associated outgoing transmission paths. The increment delays assigned to the respective buffers are calculated by a delay estimator utilizing data from the processor including packet-service times and arrival and departure times of the packets in the various buffers, the path delays assigned to routes extending from the respective transmitting buffers to a terminal node being communicated to the updating circuit via the processor from nodes connected downstream of the transmitting buffers.

Abstract: Two mutually independent clocks at a transmitting node and a receiving node of a routing network in a packet-switching telephone system are correlated by a synchronizing device associated with the receiving node whose processor, at the beginning of voice transmission between the two nodes, decodes a label of an incoming packet to determine its time of departure t.sub.s from the transmitting node whereupon a control unit at the receiving node adjusts the local clock in conformity with an estimated reading t.sub.x of the remote clock. This adjustment takes into account only fixed network parameters determining a minimum transit time for the packets by introducing a basic delay T.sub.d. After the correlation, an initial packet of a sequence representing a period of coherent speech --termed talkspurt--is stored for a time sufficient to augment the basic delay T.sub.d by a supplemental time lag T.sub.