Abstract: A subscriber line signalling apparatus for use in an asynchronous mode communication system includes a switching circuit having a plurality of input terminals and a plurality of output terminals. The switching circuit selectively communicates fixed length information packets to an adaptation processing unit. The adaptation processing unit reassembles the fixed length packets to signalling frames, and transmits them to a frame processor.

Abstract: An adaptation processing apparatus for assembling received data units of a fixed length to provide variable length data units and transmitting the variable length data units to a plurality of variable length data unit processors while assembling variable length data units received from said plurality of the variable length data unit processors to provide fixed length data units for transmission thereof. An ATM switching system includes the adaptation processing apparatus, a signal processing unit including the plurality of variable length data unit processors mentioned above, and first-in first-out mechanisms for the variable length data units provided in the adaptation processing apparatus in association with every one of the plural variable length data unit processors.

Abstract: In a network system in which an interconnection is achieved between an LAN terminal connected to an LAN and an ISDN terminal linked with an ISDN via at least an LAN/ISDN inter-working unit coupling the LAN with the ISDN, the ISDN terminal develops a function to multiplex data link connections (communication paths) identified with respective data link connection identifiers (DLCIs) on ISDN channels. After conducting a call establishment to the ISDN terminal, the inter-working unit supplies the LAN terminal with an ISDN channel number and a DLCI designating an ISDN communication path. Thereafter, the LAN terminal sends an LAN frame having an OSI layer 2 header loaded with the communication path information to the inter-working unit. On receiving the LAN frame, the inter-working unit executes a format conversion to convert the LAN frame into an ISDN frame based on the ISDN communication path information.

Abstract: A subscriber line signalling apparatus for use in an asynchronous mode communication system includes a switching circuit having a plurality of input terminals and a plurality of output terminals. The switching circuit selectively communicates fixed length information packets to an adaptation processing unit. The adaptation processing unit reassembles the fixed length packets to signalling frames, and transmits them to a frame processor.

Abstract: A packet switching equipment housing therein a plurality of pairs of an input line and an output line is provided with a monitor circuit for monitoring a packet congestion state in the packet switching equipment for each output line. When a packet congestion is detected in association with either one of the output lines, a congestion indicator is added to a packet to be delivered to the output line so as to return the packet as a congestion notice packet to an equipment as the transmission source of the packet; furthermore, the input packet is relayed via the output line to the destination equipment.

Abstract: In a distributed network formed of communication stations having equal control functions, each station which sends a master station (or Active Monitor) determination frame appends a unique identifier to the frame, and each station which receives a frame judges the rationality of the received frame based on the identifier thereby to determine the operation of the self station depending on the result of judgement.

Abstract: A method for performing a duplicated address test used for a network including a first ring transmission line, a second ring transmission line having a signal transmission direction opposite to that of the first ring transmission line, and a plurality of stations connected to at least one of these ring transmission lines. Each of these stations has a flag DAC representing whether or not the duplicated address test is performed, and some of the plural stations constitute a plurality of control nodes having a configuration function of the network. The flag DAC of each of the stations is reset at a time instant when a power source of this station is turned on, and also when any of the control nodes receives the sent out configuration control frame. Each of the stations having the reset flags DAC sents out the duplicated address test frame to either the first or second transmission line to which the station is connected when a token frame to control a transmission right is captured.

Abstract: A ring network system in which a plurality of line concentrators each having terminal stations connected thereto through respective branch lines are interconnected through at least one ring transmission lines. Each line concentrator includes configuration control switches capable of disconnecting from the ring transmission line all the branch lines placed under control of the line concentrator while holding the ring transmission line in the state to allow communication. The branch line(s) disconnected from the ring transmission line form(s) a local ring through cooperation with an internal transmission line. The line concentrator detected abnormality of communication or the line concentrator to be set to the rest state can undergo internal diagnosis operation or continue to be in the rest state without disturbing the communication among other line concentrators.

Abstract: In a communication system having first and second ring transmission lines for connecting a plurality of stations and for providing opposite signal transmission direction, a first station, which is located just downstream side of a failure point occurred in the first transmission line, sends out a beacon signal along said first transmission line while causing an intentional failure in the second transmission line on its downstream side and a second station, which is located just upstream side of the failure point on the first transmission line, forms a first loop-back path (WRAPA) by detecting the intentional failure on the second transmission line if the second station has received the beacon signal. The first station forms a second loop-back path (WRAPB) by receiving the beacon from the second transmission line which is sent back by the second station.

Abstract: A data memory system includes a plurality of buffer regions each having a constant size so that serial data may be stored by linking the buffer regions. A descripter provided to correspond to each of the buffer regions includes memory region addressing information indicating the head address of the corresponding buffer region, data delimiting information indicating whether or not the data to be stored is terminated in the corresponding buffer region, and chain information indicating the head address of a next subsequent descripter.

Abstract: Herein disclosed is a communication network, in which two terminal nodes transmit and receive messages containing a destination node discriminator and a source node discriminator by way of a communication route composed of at least one relay node and a plurality of information links connecting the terminal nodes and the relay node. In this communication network, the relay node is stored in advance, in accordance with the combination of a destination node and a source node, with both the information link for transmitting the messages received and the flag information indicating the establishment of the communication route from said source node to the relay node itself.

Abstract: In a telephone switching apparatus having an inter-office interface consisting of a plurality of communication circuits having different priorities and a control line for transfer of call control signals, a first circuit having the highest priority is hunted from the idle one of said communication circuits upon setting of a call and the communication is started. During the communication, if a second circuit having a higher priority than that of the first circuit becomes idle, by communicating a control signal to switch the circuit between the switching apparatuses, the busy circuit for the call is switched from the first circuit of a low priority to the second circuit of a high priority.

Abstract: In a communication system having first and second ring transmission lines for connecting a plurality of stations and for providing opposite signal transmission direction, a first station, which is located just downstream side of an failure point occurred in the first transmission line, sends out a beacon signal along said first transmission line while causing an intentional failure in the second transmission line on its downstream side and a second station, which is located just upstream side of the failure point on the first transmission line, forms a first loop-back path (WRAPA) by detecting the intentional failure on the second transmission line if the second station has received the beacon signal. The first station forms a second loop-back path (WRAPB) by receiving the beacon from the second transmission line which is sent back by the second station.

Abstract: A station diagnosis method in a communications network system including a closed ring transmission line and a plurality of data stations which can be connected to the ring transmission line by a plurality of line concentrators disposed in the ring transmission line wherein an internal ring transmission line is formed in the line concentrators so that the operation states of the line concentrators are diagnosed by transmitting diagnosis data through the internal ring transmission line.

Abstract: In a communication network, in which a plurality of switching nodes are connected with each other through a plurality of relay lines and one of the switching nodes acts as a center node for network routing, the center node estimates the state of delay of data for every relay line on the basis of information previously inputted, indicating the communication network configuration, and the state of delay of data reported by each of the switching nodes, and informs each of the switching nodes of said estimated state of delay of data. Each of the switching nodes determines and selects the relay line giving the shortest delay of data for every destination, to which it outputs data, on the basis of the state of delay at the relevant switching node itself and that received from the center node.

Abstract: In a communication network having a plurality of stations interconnected through a double ring transmission line, a station which detects a failure in the ring transmission line sends out a failure notice data, and a station which has received the failure notice data stops the send-out of its own data and relays the received data. A station which cannot receive the failure notice data loops back and transmission line to form a closed ring transmission line which bypasses a failure location.

Abstract: A local area network communication system in which a repeating installation sets a ring number of a ring from which a communication frame was taken out as a source address of the frame. The repeating installation also sets a ring number of a ring to which a communication frame is to be sent. When a station receives the frame, the station checks the source address of the frame to identify the ring number of the ring to which the source station belongs and checks the destination address to identify the ring number of the ring to which the station itself belongs.