Abstract: A cell multiplexer includes a multiplexing unit for time-divisionally multiplexing ATM cell signals given from a plurality of input lines, a write controller for storing cell signals outputted from the multiplexing unit in a buffer memory successively correspondingly to the input lines, a read controller for reading the cell signals stored in the buffer memory from the buffer memory in the form of data blocks synchronized with an ATM cell structure, and a cell delineation controller for detecting delineation states of the data blocks read out from the buffer memory, notifying the read controller of delineation control information corresponding to a result of the detection and transmitting data blocks read out in synchronism with a predetermined cell structure to the output line selectively, wherein the read controller determines the read beginning addresses of data blocks to be read out nextly correspondingly to the input lines on the basis of the delineation control information notified by the cell delineati

Abstract: An ATM switching system comprises a switch unit including a plurality of input ports and a plurality of output ports having the same cell transmission rate, and a multiplexer for multiplexing cell trains outputted from at least two output ports into a single cell train and outputting the cell train to a high-speed output line (and/or a demultiplexer for demultiplexing a cell train from an output port into a plurality of cell trains and outputting the cell trains to a plurality of low-speed output lines). The switch unit includes a buffer memory for temporarily storing cells inputted from the input ports while forming a queue chain for each output line to which each cell is to be outputted, a demultiplexer for distributing the cells read from the buffer memory among the output ports in circulation, and a buffer memory control circuit for controlling the write and read operation of cells with the shared buffer memory.

Abstract: A cell multiplexer includes a multiplexing unit for time-divisionally multiplexing ATM cell signals given from a plurality of input lines, a write controller for storing cell signals outputted from the multiplexing unit in a buffer memory successively correspondingly to the input lines, a read controller for reading the cell signals stored in the buffer memory from the buffer memory in the form of data blocks synchronized with an ATM cell structure, and a cell delineation controller for detecting delineation states of the data blocks read out from the buffer memory, notifying the read controller of delineation control information corresponding to a result of the detection and transmitting data blocks read out in synchronism with a predetermined cell structure to the output line selectively, wherein the read controller determines the read beginning addresses of data blocks to be read out nextly correspondingly to the input lines on the basis of the delineation control information notified by the cell delineati

Abstract: An ATM switch including ECC encoder circuits each for generating, for an ATM cell as an information symbol, an ECC check symbol and for adding the ECC check symbol thereto, cell partitioning circuits each for subdividing an information field of an ATM cell into N partial cells, for subdividing a check symbol field into M partial cells, and for assigning an identical routing tag to the obtained partial cells (N+M) partial cell switches for respectively routing the (N+M) partial cells in an independent fashion based on the routing tag, and ECC decoder circuits for receiving the (N+M) partial cells thus routed and for achieving an error correction on the received partial cells.

Abstract: An ATM switching system which includes PVC allocation circuits corresponding to output queues. At the time of arrival of the leading cell of each burst data, if the output line has room, the PVC of the burst data is stored as information for admission and identification. The subsequently-arriving cells having the same PVC identification information as the stored identification information are input to an output buffer, and the cells of the remaining burst data are all discarded. Even when a plurality of burst data compete for the same output line, the fact that all the cells other than the first-arriving admitted burst data are discarded prevents the cells from being input other than within a predetermined bandwidth and localizes the burst data affected by the cell discarding due to output queue overflow.

Abstract: An ATM exchanger includes a plurality of switch units connected in multiple stages, in which a circuit is provided for writing a test cell pattern into and reading it from a buffer memory of each switch unit in accordance with an instruction from a controller, so that the test cell read from the buffer memory can be transferred appropriately to the controller.

Abstract: A rate conversion circuit area (8) is provided between a spread gate area (4) which operates in synchronization with a clock signal CLK and a RAM core (7) (macro cell) operating in synchronization with a clock signal (ck) whose frequency is higher than that of the clock signal (CLK). With this arrangement, the single port core is made accessible as a dual port RAM by forming the clock signal (ck) whose frequency is multiplied an optional number of times that of the clock signal (CLK), receiving access data equivalent to a plurality of operating cycles in parallel from the spread gate area during a predetermined unit operating access cycle period in the spread gate area, and serially supplying these to the RAM core 7 during the plurality of operating cycle periods in synchronization with the clock signal (ck).

Abstract: In a shared-buffer-type ATM switch including a multiplexer, a shared buffer memory, a demultiplexer, a buffer memory controller, a cell copy section is disposed between the multiplexer and the memory. The copy section produces a plurality of copies of a broadcast cell according to information of a copy information table and adds associate routing information to each copied cell so as to write the cells in the memory. In response to an indication from an output counter, the cells are read from the memory to be distributed to output ports, thereby implementing a broadcast function.

Abstract: An ATM switching system which includes an input interface which is provided every incoming line and serves to convert header information of each input cell into internal routing information, a shared buffer memory and a cell writing control unit which forms normal cell list structures, which are prepared in correspondence to outgoing lines and in which a plurality of normal cells are chained together with their next addresses, and a broadcast cell list structure, in which a plurality of broadcast cells are chained together with their next addresses, in the shared buffer memory, and serves to add successively the input cells to ones of the list structures, which are selected in correspondence to respective internal routing information. The invention also includes a cell reading control unit which serves to fetch selectively the cell from the list structures formed in the shared buffer memory to distribute the cell thus fetched to the associated outgoing lines.

Abstract: An ATM switching system comprises a switch unit including a plurality of input ports and a plurality of output ports having the same cell transmission rate, and a multiplexer for multiplexing cell trains outputted from at least two output ports into a single cell train and outputting the cell train to a high-speed output line (and/or a demultiplexer for demultiplexing a cell train from an output port into a plurality of cell trains and outputting the cell trains to a plurality of low-speed output lines). The switch unit includes a buffer memory for temporarily storing cells inputted from the input ports while forming a queue chain for each output line to which each cell is to be outputted, a demultiplexer for distributing the cells read from the buffer memory among the output ports in circulation, and a buffer memory control circuit for controlling the write and read operation of cells with the shared buffer memory.

Abstract: A traffic shaping method and circuit of a packet switching system in which input packets having a fixed length and multiplexed on a plurality of inputs are multiplexed to be delivered on any output of a plurality of outputs, connects the input packet to a list structure using an address chain formed for each output, forms the list structure even for each line identifier provided in the packet, and assigns the identifier for each time slot of the output to take out the packet from the list structure, to thereby prevent the packet having the same identifier from being multiplexed and delivering to the output continuously.

Abstract: A switching system which comprises an initial stage including the plurality of first switch devices and in which respective input terminals of the plurality of first switch devices are connected in common to corresponding one incoming highway, and each first switch device selectively delivers to its output terminal an inputted packet in accordance with routing information of the packet so that packets of different outgoing highway numbers are delivered out of the output terminals of the respective first switch devices, and a final stage including the plurality of second switch devices and in which each output terminal of the respective second switch devices is connected to corresponding one outgoing highway, and respective input terminals of a particular second switch device are connected to respective output terminals of the first switch devices which deliver outgoing highways of the same numbers as those of outgoing highways connected to the particular second switch device.

Abstract: A switching system exchanges communication information as fixed length cells between a plurality of incoming and outgoing highways. The fixed length cells each have a plurality of data portions with one data portion designated as a header portion for containing switching information. An address generating circuit generates read addresses and write addresses in response to the header portion of each cell and a control circuit. The plurality of cells from the incoming highways are simultaneously rotated in a rotation matrix with each of the cell's data portions rotated to a unique internal path. The data portions are then transmitted to identical write addresses in a plurality of memories via delay circuitry. The write addresses are transmitted through shift registers to the plurality of memories to allow the data portions of a single cell to occupy identical addresses within a plurality of memories.

Abstract: In a network system having a plurality of LANs each connecting a plurality of terminals interconnected, a LAN interconnection switching unit for switching and relaying data receives data frames from LANs and sends out a call set-up frame including a call number assigned to a combination of source and destination terminal addresses and addresses of relaying interconnection switching units. The data received from LAN is segmented into packets, which are sent out together with the call number. The interconnection switching unit switches and relays data by using data frame error detection scheme in the LAN. Information for controlling a switching sequence is added to the data frame from the LAN to prevent the interruption by the packet having a different call number.

Abstract: A switching system for handling a plurality of cells, each cell including a header section and a data section, and for exchanging a communication message contained in the data section of the cell between a plurality of incoming highways and a plurality of outgoing highways according to the data contained in the header section of the cell. The switching system includes a unit for multiplexing the incoming highways in time division, a first memory having addressable storage locations for storing cells received from the multiplexing unit, a unit for demultiplexing and distributing data output from the first memory among a plurality of outgoing highways, a second memory for storing an empty address of an empty storage location of the first memory, a unit for controlling the write and read operations of the first memory in accordance with an empty address stored in the second memory used as write and read addresses, and a unit for detecting an error in at least one of the write address and read address.

Abstract: A switching system for switching communication information between "M" incoming highways and "N" outgoing highways by using fixed-length cells, each having a header section and a data section and according to information contained in the header section (where "M" and "N" are integers), comprising: a demultiplexing unit for demultiplexing each incoming highway into a plurality of first output links; a switch unit, having the first output links of the demultiplexing unit as first input links and a plurality of second output links, for switching communication information between the first input links and the second output links; and a multiplexing unit, having "N" groups of input links, each group being formed by grouping a specified number of second output links, for multiplexing the cells on the second output links of each group and outputting them through one of third output links to a corresponding outgoing highway.

Abstract: In a netowrk system having a plurality of LANs each connecting a plurality of terminals interconnected, a LAN interconnection switching unit for switching and relaying data receives data frames from LANs and sends out a call set-up frame including a call number assigned to a combination of source and destination terminal addresses and addresses of relaying interconnection switching units. The data received from LAN is segmented into packets, which are sent out together with the call number. The interconnection switching unit switches and relays data by using data frame error detection scheme in the LAN. Information for controlling a switching sequence is added to the data frame from the LAN to prevent the interruption by the packet having a different call number.

Abstract: In a packet exchange system for preforming packet exchange by setting logical channels, individual input packets are assigned with information indicative of input sequence of the individual input packets counted in each call and the input sequence information is stored. Each time each packet is delivered, the input sequence information assigned to an input packet is stored as an output sequence information in a call to which the delivered packet belongs, and the status of congestion of packets of the call which are present in the exchange is decided on the basis of the stored input sequence information and output sequence information.

Abstract: A fixed-length packet switching system, in which fixed-length packets (cells) each composed of a header portion and a data portion are received from a plurality of input lines, and after conversion of the header portions, the received packets are transmitted onto selected ones of output lines designated by their header portions.

Abstract: A CODEC including a coder and decoder to construct the subscriber's circuit of a digital telephone switching system or the like, wherein an analogue balancing circuit is provided between the output terminal of a post-filter and the input terminal of a pre-filter in order to effectively eliminate a return signal in the case of two-wire/four-wire conversion, and return signals not eliminated by the analogue balancing circuit are further eliminated by a digital balancing circuit.Especially in the present invention, the analogue balancing circuit is so constructed that its characteristics are independent of frequencies, and hence, the analogue balancing circuit and the digital balancing circuit are readily implemented as an LSI.