Abstract: A cell switch module having a unit cell switching function and placeable in either an active state or a standby state. The module comprises a plurality of input ports for inputting cells thereto, a plurality of output ports for outputting cells therefrom, and a cell switching controller to execute such control that, in response to an active/standby switching instruction, a decision is made as to whether the input cell is a specific first cell or not, and if the input cell is detected to be the first cell in the active state, any subsequent cell inputted thereafter is not switched, but if the input cell is detected to be the first cell in the standby state, any subsequent cell inputted thereafter is switched.

Abstract: A start/stop setting section is provided on the upstream side of a dual-configuration ATM switch, and a start/stop detection section is provided on the downstream side for each of a working and a protection line. At the initiation of quality monitoring, the start/stop setting section sets a start bit in an incoming cell having a specified identifier, and thereupon starts counting the number of cells whose identifier matches the specified identifier. The start/stop detection section, upon detecting the cell having the start bit, starts counting the number of cells whose identifier matches the identifier of the detected cell. At the end of the quality monitoring, the start/stop setting section sets a stop bit in an incoming cell having the specified identifier, and thereupon stops the counting of cells.

Abstract: An apparatus is described to implement a module redundant system using logical addresses. The apparatus may comprise a bus on which a plurality of server modules may be coupled to. One of the server modules may be configured to be active and remaining server modules may be configured to be on standby. A plurality of client modules may be coupled to the bus and configured to be in communication with the active server module using logical addresses.

Abstract: A method for switching a plurality of central devices including N working central devices and one protection central device of a N+1 redundancy structure provided on a LAN center, to the CATV transmission path side of which terminal devices are connected each through a cable modem, having router functions forming segments respectively at the sides of the LAN center and the CATV transmission path, and a working central device transmitting routing information of the segment on the CATV transmission path side to inform the LAN center segment of an existence of the segment on the transmission path side, so that the terminal devices are connected to appropriate networks via the LAN center, the method comprising the steps of maintaining control information of the plurality of working central devices and the protection central device to be monitored, detecting failure of a working central device by regularly polling the N working central devices, switching the detected, failed working central device to the prot

Abstract: A method and a system for implementing leaf node proxy in a network are disclosed. In one embodiment, a leaf node is switched to a standby state in response to a standby command. A leaf node self-identification (“self-ID”) packet is synthesized in response to leaf node information, which is stored in a parent node. The leaf node self-ID packet is transmitted from the parent node in response to a request.

Abstract: A switchboard system includes an input/output section, first and second switches each for acting an active side switch or a standby side switch, a signal processing section for processing received cells, and a control section. The control section switches active side ascending cell routes from the then active side switch to the then standby side switch, transmits a plurality of specified cells through the active side switch to te signal processing section, and receives the specified cells through the active side switch, and switches active side descending cell routes from the then active side switch to the then standby side switch.

Abstract: A fault tolerant switching architecture is provided with two separate switch fabrics each having a switch cure located in a centralized building and a set of SCAL elements distributed in different physical areas. Each SCAL element has both a SCAL receive element and a SCAL transmit element for access to a corresponding input and output port of the swatch core. A set of port adapters is distributed at different physical areas, with each connected switch fabrics via a particular SCAL element so that each switch core receives the sequence of cells coming from any port adapter and conversely any port adapter may receive cells from either one of the switch cores. Each switch fabric can detect an internal breakdown condition occurring in one of its element and send an error control signal to the peer element located in the other switch fabric.

Abstract: A hit-less cell switching device capable of switching ATM (Asynchronous Transfer Mode) cells between a system ZERO and a system ONE is disclosed. The system ZERO includes a first cell switch, a first input cell gate, a first output cell gate, and a first shaper. Likewise, the system ONE includes a second cell switch, a second input cell gate, a second output cell gate, and a second shaper. First, a controller opens the first and second input cell gates and first output cell gate, closes the second output cell gate, and puts the first and second cell switches and first and second shapers in a fully switched condition, thereby initializing the switching device. Subsequently, the controller closes the second input cell gate, evacuates queue buffers included in the second cell switch and second shaper, and opens the second output gate. After putting the two cell switches and two shapers in an in-switching state, the controller closes the first input cell gate and opens the second input cell gate simultaneously.

Abstract: A system and method are disclosed for maintaining the state of a virtual connection supported by an active connection manager on a standby connection manager. The method includes configuring the standby connection manager to include a physical machine object that stores a physical IP address of a physical machine that is available to the active connection manager and a virtual machine object that stores a virtual IP address of a virtual machine that is implemented on the connection manager. A replication packet is received at the standby connection manager from the active connection manager wherein the replication packet includes a foreign IP address, the virtual IP address and the physical IP address. A standby connection object is stored in the connection manager. The standby connection object includes the foreign IP address, the virtual IP address and the physical IP address from the replication packet on the standby connection manager.

Abstract: An apparatus and method for switching redundancy control which provides fast switching from a malfunctioning component to a redundant component with minimum data flow interruption for both transmitted and received data. The redundancy control system having an APS (Automatic Switching Protection) Hub, at least a working and a redundant tributary card, a bridge to provide identical traffic to the working and redundant tributary cards, a working and a redundant STM switching fabric, selectors within the working and redundant STM switching fabrics for selecting the traffic from the working tributary card to further process, a working and a redundant ATM switching fabric, a working and a redundant ATM processor and ATM selectors for selecting traffic needing cell switching from the working STM switching fabric to process further.

Abstract: An interface apparatus includes first and second devices, each having a series of ports for connection to a common packet transfer bus associated with a controller. The devices operate in parallel and are configured so that when one is in an active mode the other is in a warm stand-by mode ready to become active in the event of failure of the active device. The ports of the device in the active mode communicate normally with the controller to initiate transfer of the packets over the packet transfer bus. The ports of the device in the standby mode are inoperative to communicate with the controller to initiate packet transfer, but otherwise operate normally so as to be ready for immediate activation in the event of failure of the device in the active mode.

Abstract: A terminal device is provided for communicating data signals with a central communication device via a first signal carrying line and a second signal carrying line. The first signal carrying line is arranged for transporting a first signal and the second signal carrying line is arranged for transporting a second signal, wherein the first and second signals have equal content. The first signal carrying line has a first propagation time and the second signal carrying line has a second propagation time, such that the first propagation time is shorter than the second propagation time. The terminal device includes a signal quality comparison element for determining a first signal quality of the first signal and a second signal quality of the second signal, for comparing the first and second signal qualities, and for accepting the one of the first and second signals that has a better quality.

Abstract: The present invention relates to a guard apparatus for avoiding the malfunction of a communication apparatus due to an error in the received data in the specific location of a frame on the receiving side of an optical communication system using a SONET/SDH network. If a B2 error, a frame pattern error or an out-of-frame is detected for a received frame, this guard apparatus stops the operation for tri-stage protection for the data of the K1 and K2 bytes, and outputs data outputted for a received frame received one frame before the above-mentioned received frame. If these errors are not detected, the guard apparatus selects and outputs the non-protected data of the K1 and K2 bytes in the above-mentioned received frame. Thus, the extraction of data with an error due to an optical degradation can be avoided and thereby the malfunction of a communication apparatus in an optical communication system can be avoided.

Abstract: An apparatus and method for a communications network including at least one interface circuit reads frame data received from the communications network and writes frame data to be transmitted over the communications network, the frame data including a plurality of transport overhead fields. The apparatus includes signature logic coupled to the interface circuit, the signature logic identifying signature data and writing the signature data into transport overhead fields in an outgoing frame. Reflector logic coupled to the interface circuit copies data from one of the received transport overhead fields, the copied data being placed into a transport overhead field in the outgoing frame, the copied data including the received signature data. The interface circuit compares the copied data to earlier received frame data from the communications network, the determination of a mismatch identifying a transition requiring an update of at least one routing table.

Abstract: A switchboard system includes an input/output section, first and second switches each for acting an active side switch or a standby side switch, a signal processing section for processing received cells, and a control section. The control section switches active side ascending cell routes from the then active side switch to the then standby side switch, transmits a plurality of specified cells through the active side switch to the signal processing section, and receives the specified cells through the active side switch, and switches active side descending cell routes from the then active side switch to the then standby side switch.

Abstract: A Fault Tolerant Dial Router (FTDR) includes redundant subsystem resources that operate independently of telephone line interface connections. The redundant resources are switched active when a failure is detected in an activated dial router subsystem. Switching out subsystem failures is fully automated under software control, providing uninterrupted service to users with limited performance loss. The FTDR includes a switching mechanism that selectively switches out the telephone interfaces or other subsystem resources inside the dial router box detected as having failures. The subsystem resources include line framers, controllers and modem modules.

Abstract: A data link layer processing (DLLP) system comprises a plurality of in-service DLLPs and a plurality of spare DLLPs. The switching between the in-service DLLP and the spare DLLP is effected by coupling both the DLLPs with the transmission line and transferring logical links from the in-service DLLP to the spare DLLP one by one while frame multiplexing the data from the spare DLLP with the data from the in-service DLLP. After all of the logical links are transferred, a switch decouples the in-service DLLP to leave the spare DLLP coupled with the transmission line for a normal operation.

Abstract: A method for creating and resolving split VLANs in ATM networks. The method utilizes a Network Management System (NMS) and a standard management protocol such as SNMP. The method monitors the network by continuously polling all the devices in the network. Status related information collected by the NMS is used to construct a physical and logical topology of the network. In response to the detection of one or more physical splits in the network, the NMS creates one or more corresponding logical splits in the network by splitting one or more VLANs. In the case of two split portions, the split VLAN can be created if a redundant LES and second LECS are located on the side of the split which does not include the primary LES. The second LECS is configured to use the address of the redundant LES in replying to requests to join an ELAN from the disconnected LECs.

Abstract: A system switching over method and apparatus for duplicated ATM (asynchronous transfer mode) switch, which enables keeping the delay quality of each cell unchanged without any cell loss, are realized. At the time of system switching over, the system-switching control unit in each system (a system previously in operation and a system newly in operation) mutually communicates each other and manages a temporary cell storage unit, in which cells to be read out are stored in accordance with the delay priority group, in each system, and reads out cells in the order of higher delay priority whichever the system is. A delay priority selector in the system of an operation state is controlled to provide a cell read out path for outputting cells depending on a system from which the cell being read out.

Abstract: A first end-to-end connection between a source node and a destination node is established. The first end-to-end connection may include a number of point-to-point links between a number of intermediate nodes. At the same time, a second end-to-end connection is established between the source node and the destination node. The second end-to-end connection may also include a number of point-to-point links between a number of intermediate nodes, however, at least some of the point-to-point links and intermediate nodes which make up the second end-to-end connection are distinct from those which make up the first end-to-end connection. The source node stores connection information for both end-to-end connections. The source node establishes a session across the first end-to-end connection and, upon recognizing the failure of this connection, switches the session the second end-to-end connection automatically.

Abstract: The invention relates to a redundant switching arrangement using a first and second switching network (SWF_A, SWF_B) or other switching element. The switching elements are used to carry out switching operations in the same way, so that one of the switching elements serves as an active switching element whose switching operations are utilised, while the other switching element serves as a passive switching element backing up the active switching element. To ensure that any faults occurring in the switching elements in such a redundant switching arrangement are detected as quickly as possible, their operation is monitored by comparing the data of the corresponding output channels of the first and second switching elements, and if such a comparison shows that the data contained in any of the corresponding output channels are not identical, an internal test is carried out for at least one of the switching elements to verify the data of the output channel involved.

Abstract: A system provides automatic protection switching in case of failure or degradation in a function. For example, a system node may have a working server function, a protection server function, one or more client functions, and a control function. In its baseline configuration, the working server function is active, meaning that it is operating on-line with respect to the client functions, while the protection server function is standby, meaning that it is either inactive (i.e., cold standby) or operating off-line with respect to the client functions (i.e., hot standby). The control function monitors the operations of the working server function, and, if a failure or degradation is detected, or if an externally generated switch command is received, the control function will (1) instruct the working server function to change its status from active to standby and (2) instruct the protection server function to change its status from standby to active.

Abstract: A transport interface (10) provides add drop multiplex functionality and termination requirements for the transportation of network traffic. The transport interface (10) includes high speed units (12), broadband interfaces (16), and SONET formatters (18). Each high speed unit (12), broadband interface (16), and SONET formatter has redundant protection pairs (A and B). The high speed units (12), broadband interfaces (16), and SONET formatters (18) communicate with each other by in-band datalinks (40). The redundant protection pairs (A and B) communicate with one another by protection pair datalinks (42). The in-band datalinks (40) and the protection pair datalinks (42) provide protection switching within the transport interface (10) in the event of component failure. The in-band datalinks (40) are generated out of available or consumed bytes within either a section overhead (32) or a line overhead (34) of SONET OC-N frame (30).

Abstract: In an output port switching device in an N-WDM system, plural ports are switched by a change-over switch 18, and a backup light source path 19 linked to the change-over switch 18 has a wavelength-variable light source 23. A first multiplexer 14 wavelength-multiplexes plural optical signals output from the plural ports, and a trouble-occurring port monitoring mechanism portion 17 monitors occurrence of a trouble on the basis of an optical signal split from the output optical signal. The change-over switch 18 selects and switches an optical signal to which the trouble is detected, and the backup light source path 19 is controlled so that the wavelength thereof is substantially coincident with the wavelength of the optical signal to which the trouble is detected, and the optical signal thus controlled and the output optical signals of the first multiplexer are multiplexed by a second multiplexer 15.

Abstract: A method and apparatus for switching from an active to a standby controller in a redundant duplex carrier system without requiring retransmission of messages in progress during the switch. A main processor in the standby controller is periodically switched and made the active controller to ensure reliability of the system. The main processor in the active controller stops sending messages for a period of time before switching control to the standby controller. The main processor in the standby controller delays initiating any new communications until any current messages have been completed from the active controller. The main processor of the standby controller then retrieves any unprocessed messages that may have been sent to the active controller just before or during the switch from the active controller to the standby controller. The delay of new messages and retrieval of any unprocessed messages ensures that no data will be lost during the switch, thus removing the need for retransmission.

Abstract: An exchange system comprises a main device including a plurality of interface sections each containing one of an extension terminal, an office line, and a private line, and a plurality of exchange control systems. The exchange system also comprises a control data management device connected to the main device and including a data storage section for storing a number of control data items, wherein each of the plurality of exchange control systems includes an exchange section for arbitrarily exchanging connections of the interface sections, and a first request section for requesting a control data item necessary for an exchange service to be provided, from the control data management device. The control data management device includes a requested data output section for reading the control data item requested by the first request section and for outputting the control data item to the main device.

Abstract: A Local Area Network (LAN) Switch includes conventional switching functions and integrated Remote Monitoring (RMON) Universal Feature Card (UFC). The UFC allows simultaneously statistically monitoring the traffic on all ports, 100% monitoring of the traffic on one port, and monitoring the internal LAN Switch switching fabric to obtain RMON statistics about the operation of networks attached to the LAN Switch.

Abstract: A data communications switch and method of operation are presently disclosed enabling flexible, selectable provision of a common timing signal for synchronized external communication through physical layer interfaces with other network devices, synchronized internal communications within the switch, and for uninterrupted synchronization of such communications. Synchronization of external communications is enabled by programmable selection from among plural potential timing references at redundant timing modules (TMs). An active TM provides a primary external synchronization clock; a standby TM provides a redundant timing function. Both TMs access the same references. A state signal indicates which synchronization clock is active. External interfaces derive timing from this distributed clock. Synchronized internal timing is provided by an internal clock and phase-locked loop (PLL) on each TM. The clock/PLL timing signal output is routed to other switch elements, enabling synchronized internal data transfer.

Abstract: A communication node, for use in an inter-processor communication system in an asynchronous transfer mode switching system, provides two independent paths to upper layer switching modules for two duplicated processors, respectively, wherein the path from the processor to the upper layer switching modules includes the communication node, a node switching device, all devices are duplicated and operate by using an active and stand-by scheme, data transmitted is transmitted in the unit of a data packet and the data packet includes an information field, a node address field and a payload type field for representing whether data is switching inforamtion or not. The node comprises two subnodes controlled by the controller for the active and the stand-by processors, respectively. Each subnode has two buffers for storing received data and sending data.

Abstract: A transport interface (10) provides add drop multiplex functionality and termination requirements for the transportation of network traffic. The transport interface (10) includes high speed units (12), broadband interfaces (16), and SONET formatters (18). Each high speed unit (12), broadband interface (16), and SONET formatter has redundant protection pairs (A and B). The high speed units (12), broadband interfaces (16), and SONET formatters (18) communicate with each other by in-band datalinks (40). The redundant protection pairs (A and B) communicate with one another by protection pair datalinks (42). The in-band datalinks (40) and the protection pair datalinks (42) provide an effective means for performing protection switching within the transport interface (10) in the event of component failure. The in-band datalinks (40) are generated out of available or consumed bytes within either a section overhead (32) or a line overhead (34) of SONET OC-N frame (30).

Abstract: In a method implementing redundancy in LAN/WAN bridging/switching elements, LAN/WAN traffic is sent to active and inactive elements using multicast techniques. The active element bridges the data traffic and the inactive drops it.

Abstract: The invention concerns a method of transmitting data reliably over N normal channels (3), where N.gtoreq.1, and over at least one back-up channel (4), between a transmit end station (1) and a receive end station (2), the data transmitted comprising both traffic data and supervisory data. According to the invention, the following successive steps are performed in said transmit end station (1): the traffic data and the supervisory data applied to each of the N pairs of inputs are multiplexed on a respective one of the N normal channels; then, the multiplexed data from a "backed-up" one of the N normal channels is switched to the back-up channel.

Abstract: A redundant switch (50) is provided for performing a switch fabric test. The redundant switch (50) includes a foreground switch fabric controller (24) for controlling a foreground switch fabric (26), a background switch fabric controller (124) for controlling a background switch fabric (126), and a first I/O module (14) in communication with the foreground switch fabric controller (24). The first I/O module (14) sends, at the request of the foreground switch fabric controller (24), a test cell to an input of the background switch fabric (126) and receives the test cell from a corresponding output of the background switch fabric (126). The first I/O module (14) determines if an error occurred and provides an error signal to the foreground switch fabric controller (24) in response if an error occurred. The foreground switch fabric controller (24) may log the error signal or enable an alarm or indicator in response.

Abstract: An instantaneous switching unit for a delay/priority control buffer comprises an operational buffer and a standby buffer, wherein, upon detecting phase adjustment cell out of received signal cell, the operational buffer recognizes the amount of main signal cell which has been received before the phase adjustment cell is detected, the main signal cell staying waiting for the timing when it is read out, and notifies the standby buffer of staying amount information indicating the presence of the main signal cell staying there as well as the staying amount thereof, while the standby buffer controls the reading operation of the main signal cell according to the staying amount information received from the operational buffer upon detecting the phase adjustment cell out of the received signal cell.

Abstract: A redundancy switch (44) provides interfacing of network signals to spare network processors (46) in the event of a failure of a main network processor (42). A redundancy switch (44) allows for monitoring and diagnostic operations to be performed on network electrical signals without interrupting traffic flow on inbound and outbound paths. A redundancy switch (44) performs a loopback diagnostic by routing signals from transmitter portions of the spare network processors (46) to selected receiver portions. The redundancy switch (44) includes a receiver interface unit (90) and a transmitter interface unit (92) capable of routing inbound and outbound customer signals to and from the spare processors (46) for monitoring, diagnostic, and sparing purposes.

Abstract: A plurality of switching modules arrayed in a plurality of columns and in at least one row switch over paths in accordance with path data contained in cells to transfer inputted data to a target line on the cell-unit. One or more path switching units are provided between two adjacent columns of switching modules among plural columns of switching modules and switch paths between the respective switching modules, disposed in a side-by-side relationship in a row direction, of one column of switching modules of the two adjacent columns of switching modules and the respective switching modules, disposed in the side-by-side relationship in the row direction, of the other column of the two adjacent columns of switching modules.

Abstract: An ATM exchange network system in which a first equipment and a second equipment are connected through a duplex communication line comprising a working line and a protection line. In this system, each of the first equipment and second equipment provides: a bridging unit which bridges the working line and the protection line on the transmission side; a switch for selecting the working line or the protection line on the reception side; a K-byte generating function for generating byte information containing information for realizing the APS; a function of receiving the K byte information from the protection line, analyzing the received information, placing the prescribed information in the K byte and realizing the APS; and a function of changing over the switch. Thus, the reliability with respect to a line failure in the ATM exchange network can be improved.

Abstract: A device for duplicating a connectionless server whose reliability and performance are improved includes a physical hierarchy processor for converting connectionless input data into an electric signal, outputting the matching signals by ATM physical hierarchy processing of the converted signal, and processing the input signals in its reverse order; a duplication cell processor for performing a header conversion processing operation with respect to an input cell of the matching signals according to its destination address, and enabling only buffers of one-side cell processor according to a signal state decided by an inner duplication state decider, with respect to the cell which completes the header conversion processing operation; and a duplication controller for maintaining, repairing, multi-casting and connection-controlling cells applied from the duplication cell processor, the duplication controller enabling and outputting only buffers of one-side controller according to a signal state decided by the inne

Abstract: The main storage, the communication interface portion and the circuit control module hold transmission data in the buffers until completion of the transmission has been confirmed. When a fault has occurred in the current operating system of the duplexed portions in the configuration elements of the host computer and the multi-circuit control unit, the duplexed portions are changed over from the current operating system to the stand-by system. In this case, information for reproducing data that has been lost due to the change-over is transmitted from the main storage and the circuit control module to the communication interface portion which has become the new current operating system. The communication interface portion which has become the new current operating system restarts the processing based on this information.

Abstract: A line switching apparatus is applied to a system which has a current system line and a spare system line, transmits identical ATM cell streams via the two lines, and adds protection switching cells to the ATM cell streams on a transmission side when line quality of the current system line deteriorates. The apparatus is adapted to switch a line to be used from the current system line to the spare system line in the system. The apparatus includes a first VPI converter, a multiplexer, a spare system line information read section, and a second VPI converter. The first VPI converter converts the VPI of the spare system line into a VPI different from the VPI of the current system line.

Abstract: Redundant facility payload signals (12, 14) received by redundant interface modules (16, 18) are redundantly provided (28, 30; 32, 34) to redundant downstream modules (24, 26) in an equipment (10). A non-symmetrical facility protection algorithm is resident in the B interface module (18). Symmetrical equipment protection algorithms are independently resident and operative in each module of pairs of identical A and B modules at each stage of the data stream. Module or data failures result in switchover only of the disabled data path or module so that the ability to transport payload is maintained and other modules or data paths are unaffected. Facility switchover is effected by detecting a working line failure and transmitting commands to switch the protection line to the A path modules. Equipment switchover is effected by checking for a working or protection module failure independently in each path and independently communicating independent switchover decisions to the other side and downstream.

Abstract: The ATM switch includes a switch network section, a common section and an individual interface section. The ATM switch system can reduce a cost by sharing the common section in both cases of employing a simplex and a duplex individual interface sections. The common section includes a demultiplexer, a user cell discarding section, a header convertor, a multiplexer, an individual interface section information receiver, and a controller. The individual information receiver identifies whether the individual interface section has a simplex or a duplex structure according to information sent from the individual interface section. The controller sets the condition of demultiplexing the cells in the demultiplexer, and sets the condition of discarding the user cells in the user cell discarding section.

Abstract: For synchronization signals of zeroth and first series, a synchronization signal processing system comprises synchronization trunk device of the zeroth and the first series (77(0), 77(1)) for producing particular signals of the zeroth and the first series, respectively, and being exclusively operable in master and slave states.

Abstract: Transmission line interfaces 300 and 400, terminal interfaces 100 and 200 and a time switch (TSW) 500 are controlled by a controller 600'. The controller 600' includes a communication means circuit 70 for communication with the controllers of other stations, a TS allotment data memory 80 accommodating ID number data provided corresponding to each path in TS allotment data describing the allotment of specific time slots (TS) to transmission lines 30 and 40, a route data table 60 accommodating route data constituted by data sets of the station numbers and ID numbers of stations until reaching of an end station for each ID number path, and route data updating means (not shown) for updating route data. Working path data can be obtained with reference to the route data.

Abstract: A line protection switching system of a duplexed fiber interface shelf makes easily to reconcile conditions of duplexed fiber interface shelves, which perform line switching by employing APS bytes on an ISDN network. The line protection switching system has a pair of duplexed line switching controllers that send a line switching control signal to switch the transmission lines and a pair of duplexed line interface devices operatively connected to the pair of duplexed line switching controllers. An active interface device of the duplexed interface devices receives the line switching control signal only from an active line switching controller of the duplexed line switching controllers and echoes the received control signal back to the duplexed line switching controllers.

Abstract: Switching equipment in provided for performing a switching process of a fixed length cell consisting of data and a cell header. A line interface provided in the switching equipment accommodates a plurality of lines and, at the same time, processes the data from each line on a cell unit. The line interface includes individual units and a common unit. The individual units are individually connected to the plurality of lines accommodated therein and individually process the cells. The common unit is connected to the individual units and, at the same time, effects batch-processing of the cells processed by the individual units.

Abstract: In a device and a method for performing a switching control to a standby system in a hybrid system including a duplex system and a backup line, communication is performed without using a backup line when a line is switched in an exchange. The device includes a first exchange having a pair of communication multiplexers and a communication line management processor. The backup line uses a public network. A second exchange is provided for interchanging between a line connected via the first exchange and the backup line using the public network. A normal notification signal is transmitted to the opposite communication party or second exchange when one of the communication multiplexers is switched to the standby system. A regulation releasing signal is transmitted after the switching operation so that communication is performed without using the backup line.