Abstract: In a communication network in which one master device and a plurality of slave devices are connected via a multiplexer to each other in a tree form with the master device provided at the vertex, the master device specifies each of the slave devices via the multiplexer according to a round-robin. Then the slave device transmits specific information for starting used for matching the sampling time to the master device according to the specified order. Finally, the sampling time is adjusted by executing a prespecified operation according to the specific information for returning returned from the master device in response to the specific information for starting.

Abstract: Each of terminal equipments (11, 12) and multiplexing equipments (13) transmits a synchronization control packet to an adjacent terminal equipment or relay equipment in synchronism with an own synchronization timing signal. In the wake of the synchronization control packet, each of terminal equipments and multiplexing equipments transmits information packets having a length and a number predetermined for each terminal equipment, toward an opposite terminal equipment. Each of the terminal equipments (13) temporarily holds information packets received between the current synchronization timing signal and the next synchronization timing signal, and relays the held information packets in the wake of the synchronization control packet in synchronizm with the next synchronization timing signal.

Abstract: A multicast connection control apparatus provided in a branching-and-consolidating node connecting a source terminal to a plurality of destination terminals for branching information over the forward connection or consolidating information over the backward connection in a multicast connection ATM network system includes a congested status management table for managing congested status in all RM cells and a controller. The controller transmits only an uncongested status RM cell transmitted thereto last over the backward connection when all the connections in a sequence are found to be in the uncongested state. The controller also transmits only a congested status RM cell over the backward connection when one of the connections is found to be in the congested state and cancels the subsequent transmission of the congested status RM cells in the same sequence over the backward connection.

Abstract: An asynchronous transfer mode (ATM) communication network system is constructed by connecting a plurality of ATM terminal communication devices to each other through connections. Each ATM terminal communication device has a transmission function to transmit an output ATM cell and a receiving function to receive an input ATM cell.

Abstract: In an ATM communication network system comprising plural ATM terminals 1a to if respectively having individual real memories 38a to 38f to transmit and receive ATM cells and ATM switching apparatus 2a, 2c and 2e for switching the ATM cells transmitted and received among the ATM terminals 1a to if and setting a broadcast connection 4a designating the respective ATM terminals 1a to if as the transmitting ATM terminals, the virtual memory 3 may be realized on the real memories 38a to 38f of the ATM terminals 1a to if by periodically performing the broadcast cell communications using the broadcast connection 4a designating all the ATM terminals 1a to if in the present system as the transmitting apparatuses.