Abstract: A communication network (VCN) offering an ETHERNET service to a plurality of local terminals (ELT1, ELTN, TLT1, TLTN1-8), typically computers, is proposed. Flexibility and cost are enhanced with respect to existing ETHERNET networks by emulating an ETHERNET network towards the local terminals while pooling complex functions in a computer network server (LANS) connected to the backbone ATM network (BB). This is achieved by coupling the local terminals, preferably separately, to standard ETHERNET links (ELN, TL1, TLN1-8) and by terminating these links in interface modules (EIM1, EIMN, TIM1, TIMN) converting the ETHERNET frames from the local terminals in ATM packets destined for the central server which stores these packets in an input buffer (IB1-X) and performs the above complex functions, particularly also the transmission of these packets to appropriate ones of the interface modules.

Abstract: A communication system includes a main station (MS) and a plurality of substations (SX/SZ) which include each a transceiver and are all connected in parallel to first (UL) and second (DL) unidirectional links on which recurrent first and second cells of fixed length are transmitted in opposite direction. Each of these cells contains a plurality of signalling channels smaller than the number of substations. When a substation has to transmit data it starts an allocation procedure wherein the substation cooperates with the main station and by which a channel is allocated to it. Afterwards prior to transmitting the data the substation transmits a request signal in the allocated channel and starts transmission after having received from the main station a grant signal in the homologous signalling channel of a second cell. De-allocation of a channel occurs as soon as the latter is no longer needed.