Abstract: A picture distribution service system carries out a distribution control of picture information service in a broadband transit switching network having a hierarchical structure. The system comprises a plurality of transit switches for switching transit lines through which picture information is transmitted from a source and distributed by a center switch, a first trunk part provided for each of the transit switches for distributing the picture information from the center switch to the transit lines, a plurality of subscriber switches for switching subscriber lines through which the picture information from each of the transit lines is transmitted to a plurality of subscriber terminals, and a second trunk part provided for each of the subsriber switches for distributing the picture information from each of the transit switches to the subscriber lines.

Abstract: An ATM multiplex transmission system including AAL processing units, an ATM cross connection processing unit, and a plurality of lines connected to the same, wherein the system has test equipment formed in it, the test equipment being formed as a particular cell generating unit and a routing information setting unit in at least one of the line corresponding points which the ATM cross connection processing unit has at the portions connecting with the lines. When a routing test is performed in the system, the VPI and the VCI designating the route are given from the outside as the routing information.

Abstract: In a congestion control system for an interface between a PBX and an ATM multiplexing transmission unit connected to a network via an ATM transmission line, a congestion detecting unit detects a congested state in which the ATM transmission line is congested with traffic. A control unit inhibits a call from the PBX from being sent to the ATM transmission line via the ATM multiplexing transmission unit when the congestion detecting unit detects the congested state.

Abstract: An amount-of-data identifying portion identifies the amount of data transmitted by referring to a specific portion in the upper layers of the information transmitted from the terminal of a LAN, and a bandwidth control line monitor portion calculates the band which is necessary for communication. Communication between LANs is executed through the number of wide area network interface portions which is determined on the basis of the calculated band. In the case that the communication is performed after securing the band corresponding to the traffic characteristics (transfer speed, etc.

Abstract: In an ATM cell assembling and disassembling method for a communications network having first and second communications nodes, HDLC data is transferred from a first terminal to the first communications node via a first transmission line, the HDLC data conforming to an HDLC format. It starts to assemble, in the first communications node, at least one cell from the HDLC data when data which is contained in the HDLC data and equal to one cell has been received. Then the above at least one cell of ATM data is transferred from the first communications node to the second communications node. Disassembly is started, in the second communications node, of the above at least one cell of ATM data to thereby generate original HDLC data when a fluctuation compensation time has elapsed after a first cell of ATM data among the above-mentioned at least one cell of ATM data is received by the second communications node.

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 synchronization circuit for ATM cells transferred in an ATM communication system, wherein the synchronization circuit receives and holds in a bit serial manner the input bit trains constituting the received ATM cells by a shift register unit, performs a CRC operation in a bit serial manner on the held input bit trains by a continuous CRC arithmetic unit in accordance with a simplified CRC operation process different from the usual CRC operation process, and performs the necessary synchronization control upon receiving the CRC arithmetic operation result at a synchronization control unit, thereby enabling CRC arithmetic operations to be performed continuously and by simple hardware on the headers in the ATM cells.

Abstract: An ATM communication system including an ATM switching network which includes a plurality of ATM exchanges and controls exchanges among a plurality of terminal equipment and a management apparatus which manages the traffic in the ATM switching network; the ATM switching network including a notifying unit which notifies the terminal equipment of the allocable bandwidth which can be used in accordance with the amount of traffic in the ATM switching network; when the notified allocable bandwidth is a bandwidth which can be used for their communication, the terminal equipment starting the communication in the range of that bandwidth.

Abstract: A change-back system is designed for an asynchronous transfer mode network in which a rerouting path is set to replace an original path when a fault is generated in the original path within the network, which network includes a plurality of communication nodes which are coupled via lines and communicate information in the form of cells, and the original path and the rerouting path couple first and second communication nodes within the network. The change-back system makes a change-back process to change the path used from the rerouting path to the original path when the fault is restored.

Abstract: A method of transmits HDLC data which is in conformance with a high-level data link control procedure via an asynchronous transfer mode network. The method includes the steps of deleting at least flags from the HDLC data before assembling ATM cells which are transmitted via the asynchronous transfer mode network, disassembling the ATM cells which are received via the asynchronous transfer mode network, and inserting at least flags to the disassembled ATM cells to restore the original HDLC data.

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.

Abstract: A switching system for a network having terminal control equipment units connected to a network termination unit, in which terminal control equipment units of the same kind are connected with an exchange through a subscriber's line which has assigned to it a single subscriber number and which has a plurality of communication channels. The system including storage units for each terminal control equipment unit of the subscriber's line for storing call status of incoming calls. When a first incoming call is received, the storage units of the terminal control equipment units set respective call status for the first incoming call to a ringing state. When a second incoming call is received before a response to the first incoming call is transmitted, the storage units also set the call status for the second incoming call to a ringing state.