Abstract: An apparatus for controlling cells which are to be input to an ATM switch includes a buffer circuit for storing a cell directed to the ATM switch, and a memory for storing, for each of different calls, the number of cells which are in the ATM switch. The apparatus includes a periodic calculation circuit for periodically changing the number of cells for each of the different calls by an operation value, and a control part for determining whether the cell stored in the buffer circuit should be output to the ATM switch or discarded by referring to the number of cells which is stored in the memory and related to the cell stored in the buffer circuit.

Abstract: A connection hold control system is adapted to a data communication system in which a data communication is alternately made between a first terminal and a second terminal and between the first terminal and a third terminal, where each of the first through third terminals is coupled to a communication network via a terminal adapter. The connection hold control system includes a hold part, provided within a first terminal adapter which is coupled to the first terminal, for holding a first channel which connects the first and second terminals via the communication network and the terminal adapters after a data communication from the first terminal to the second terminal ends, and a connect part, provided within the first terminal adapter, for connecting the first and second terminals via the first channel if a data communication from the first terminal to the third terminal via a second channel ends within a predetermined time after the data communication from the first terminal to the second terminal ends.

Abstract: An ATM exchange system includes a unit for detecting management cells from among multiplexed input ATM cells, and a path creating unit dedicated to the detected management cell. The path creating unit is activated each time the management cell detecting unit detects the management cell, and thus the management cell is transferred to the corresponding outgoing line without loss in the exchange, and can be transferred thereto before a user ATM cell.

Abstract: A routing method routes cells which are transferred through one of a plurality of paths within an asynchronous transfer mode (ATM) switching system selected by routing information. The routing method includes the steps of adding first routing information to incoming cells at an input stage of the ATM switching system when supplying the cells to the ATM switching system, generating a route switching confirmation cell in response to a route switching instruction and for adding second routing information to incoming cells thereafter so as to supply the route switching confirmation cell and the cells added with the second routing information to the ATM switching system. The second routing information is different from the first routing information and is determined by the route switching instruction, comparing routing information.

Abstract: A self-routing switching system connected between input highways and output highways, includes conversion modules, doubled SRM networks, output modules, and first and second selectors. Normally, one of the SRM networks is connected between the conversion modules and output modules through the first and second selectors. When a request to switch the active network to the other SRM network is received, the first and second selectors switch connections to the conversion modules and output modules so that the other SRM network is connected between the conversion modules and output modules. Before actually switching the connections, it is determined whether or not all cells have been discharged from the active SRM network.

Abstract: A transmission control system in which terminals are connected to an ATM switching network, has a table circuit registering virtual channels presently formed in the ATM switching network in a management table, and a retrieval part for receiving a communication request from one of the terminals and for determining whether or not the management table registers a virtual channel corresponding to the communication request. Data output from one of the terminals is transferred to a different one of the terminals addressed by the communication request through the virtual channel corresponding to the communication request and corresponding two of the terminal adapters, when the retrieval part determines that the management table has the virtual channel corresponding to the communication request.

Abstract: An information distribution system includes a node station and a plurality of terminal devices connected through transmission lines with the node station. The node station includes a distribution information storage unit for storing information which is to be distributed to the plurality of terminal devices, and a re-transmission request response unit for re-transmitting information in question in response to requests from the plurality of terminal devices. Each of the terminal devices includes an error checking unit for checking transmission failure in the data transmission based on the received information. The transmitted information is divided into a plurality of blocks, and, after the completion of reception of all block-form information, a re-transmission of information is requested, and based on this request, a re-transmission of information is carried out.

Abstract: A self-routing switching system including a route setting unit (10) which receives transmission information and identification information given from incoming lines and forms, from the identification information, control information for setting a path to one outgoing line to which the transmission information is to be transferred, and a self-routing speech path (20) which can form a plurality of paths and which selects the most suitable one therefrom by the control information and autonomously guides the transmission information to the destination outgoing line.

Abstract: Disclosed is a ring transmission system which incorporates both a narrowband network and a broadband ISDN network. The system comprises a plurality of nodes connected to a ring line. Each node comprises a drop/insert unit for dropping/inserting data by the use of a communication channel allocated to the node and an allocation changing circuit, whereby, a plurality of independent narrowband and broadband exchange networks are connected to a single ring transmission line.

Abstract: A header driven packet switching system includes packet header processing circuits for controlling the routing and header rewriting of data packets. The packet header processing circuits are the hunted type and are arranged independently from incoming lines so that a packet switching capacity of the system will be improved, a high speed packet switching realized, and an improved flexibility of the system against traffic congestion will be obtained. In addition, it is possible to arrange the packet header processing circuits according to traffic conditions.

Abstract: In a header driven type packet switching system, all incoming and outgoing lines required for the system are divided into groups to constitute a two stage structure of incoming and outgoing modules, which are prepared for the respective incoming and outgoing line groups. In each incoming module, outgoing module and outgoing line, information is given to packets, and the data packets are successively transferred from the outgoing modules to the corresponding outgoing lines. Thus, the system can flexibly cope with an increase of the incoming lines and the number of calls.