Abstract: A method of accessing a local-area network which allows transmission on a unidirectional ring, of circuit-switched or packet-switched communications organized in hybrid frames, in which overlapping between the beginning of a frame and a residual of the preceding frame which is still to reach its destination is avoided without reporting to a rigid band allotment to the indiviual communications and to a network synchronization system, where a well defined node acts as a master clock. According to the method the individual nodes of the network, access in sequence the transmission line in each frame, maintaining the same order of asynchronous access in the circuit and packet regions.

Abstract: The local network comprises a plurality of active nodes (N1 . . . Nn) placed along a folded unidirectional bus (1) which presents a writing branch (1W) and a reading branch (1R). The nodes present means (RR) for network reconfiguration in the presence of a failure, through an isolation of the parts concerned by the failure, through an isolation of the parts concerned by the failure, and for regular service restoration after the repair, and means (GA) for the implementation of an ordered access protocol, which is based on the physical position of the nodes (N1 . . . Nn) and allows hybrid frames to be transmitted through the bus (FIG. 1).

Abstract: The system comprises a plurality of units arranged along a unidirectional line whereupon information is transmitted relevant to circuit switched and packet switched communications and organized into hybrid frames comprising a region for each communication type. The units comprise devices handling the access to the line which cooperate with one another and with a frame signal generator, centralized or associated with each unit, to implement in distributed way an ordered protocol without collisions in both frame region, based on physical unit location.