Abstract: A method for controlling the number of disk revolutions in a disk drive using a zone CLV control system to reduce or eliminate the possibility of read-out errors when the data read-out position is shifted from a current zone to a neighboring zone during a sequential data read-out operation. In accordance with the method, it is determined whether or not data to be read out is sequential data, when a zone change is made. Where sequential data is to be read out, the zone change is made under the condition in which the gain of a rotation control system for the disk motor is attenuated. Where the data to be read out is not sequential data, the gain of the disk motor rotation control system is increased. Under this condition, a seek operation is executed.

Abstract: An optical disk has a recording region divided into zones, each zone including physical tracks which are divided into a number of sectors. The optical disk further includes a structure management table which stores an attribute for each zone indicating whether the corresponding zone is a recording area which permits rewriting of a recording area that does not permit rewriting.

Abstract: In recording dots corresponding to the data to be recorded in the record transmission path, the dots are recorded optically readably so that the recorded data may be reproduced by using two-dimensional interference from the adjacent dots. In reproducing data, after the code image has been processed by equalization in the PR-equalization portion, and simultaneously based upon the reading point position information detected in the reading point calculation portion, the values in the reading points are judged, and in the decoding portion, these read data are judged and decoded based upon the predetermined decoding rules, and they are converted into the original data.

Abstract: The present invention relates to a disk recording medium such as a CD or a DVD in which data is recorded in high-density, and method and apparatus for reproducing data recorded in the high-density disk recording medium. The data reproducing method and apparatus according to the present invention converts a high-frequency signal reproduced from the disk into a plurality of binary signals through comparing the reproduced signal with two or more slicing levels which are different each other, selects one of the plurality of binary signals or a periodic pulse signal based on the difference magnitude between the plurality of binary signals, synchronizes a reference clock with the selected signal, and restores the selected signal into bit stream using the synchronized reference clock.

Abstract: The optical disk apparatus is provided with a radiation shielding potion 3 including a horizontal section 31 in parallel to a bottom plate 73, and vertical sections 35, 35 which extend downwardly from both ends of the horizontal section, and provided in the vicinity of a front panel 4 to cross over a disk read section 2 equipped with a pickup 11. Further, each of the horizontal section 31 and the vertical sections 35, 35 is first shielding planes 33, 33, 37—37 in parallel to the front panel 4 and second shielding planes 32, 36, 36 perpendicular to the front panel. The vertical sections 35, 35 are secured to the bottom plate 73 at their lower ends.

Abstract: A disk drive preventing entry of air containing dust into a cartridge when a rotation table enters from an opening formed in a bottom surface of the cartridge and makes a disk-shaped recording medium rotate includes a carrier in which a cartridge accommodating a hard disk is loaded, a rotation table which enters from a disk drive opening in the bottom surface of the cartridge, clamps and makes the disk rotate when the cartridge is loaded in the carrier, and a sealing member which is attached to the carrier and which is formed with a lip in press-contact with the bottom surface of the cartridge so as to surround the disk drive opening when the cartridge is loaded in the carrier. The sealing member includes through holes through which height positioning projections penetrate to attach the sealing member to the carrier.

Abstract: An optical pickup apparatus has a light source unit that includes a first light source and a common light-receiving device having first and second light-receiving sections. The optical pickup apparatus further includes an optical path composition element that guides first light emitted from the first light source and second light emitted from another light source into an optical path that passes an objective lens, and an optical path polarization element that guides reflected lights of the first and the second lights to the common light-receiving device. The optical path polarization element is mounted in the light source unit for guiding reflected lights of the first and second lights to the common light-receiving device.

Abstract: An optical disk drive having an optical disk that permits transmission of a laser beam, an optical disk holding mechanism configured to rotatably support the optical disk, a first laser beam irradiation mechanism disposed on one side of the optical disk, causing the first laser beam to be vertically incident on one surface of the optical disk, and a first evanescent optical system disposed on the other side of the optical disk. The first evanescent optical system is configured to receive the first laser beam which emanates from the laser beam irradiation mechanism and passes through the optical disk, and radiate the first evanescent wave to the other surface of the optical disk having at least one recording surface.

Abstract: A tilt adjusting apparatus for a disk drive including a support plate which is fixed to a drive plate, and a skew plate which is fixed to a spindle motor, wherein the support plate and the skew plate is attached to each other with guide screws. The skew plate is tiltably supported by the support plate with the use of helical compression springs. The skew plate has bulged portions which abut on gradient portions formed on support plate. The skew plate also has grooves for receiving guide pins which are fixed to the support plate. An adjuster screw applies force to the skew plate in a tangential direction which is perpendicular to the tracking direction of the optical pickup, and thus performs a tilt adjustment in the tangential direction.

Abstract: An information recording medium wherein an optically detectable information recording medium is comprised of at least a substrate, a recording layer, and a resin layer. The information recording medium has surface roughness R&sgr; on the surface of the recording layer, which is in contact with the resin layer, under 5 nm. The information recording medium controls the reproduction signal noise, enables highly densified recording.

Abstract: A write-once DVD 1 has a lead-in area 4 provided inside a data area 5 where digital information on a document, image sound or the like is recorded, which includes prepits 9 holding copy managing key information for preventing unauthorized copy from a source disk to the DVD 1. The DVD has also a test area 3 provided inside the lead-in area 4, which is used for adjusting the power characteristics of the DVD 1. In the DVD 1, information recorded in the source disk can be. physically prevented from being copied into the DVD 1 without good cause on the basis of the copy managing key information recorded in the prepits 9.

Abstract: There is provided a rewritable multilayered disc having a plurality of recording layers. At least one of the plurality of the recording layers has a layer information region for recording layer information which includes recording prohibition information. The recording prohibition information indicates whether or not user data is prohibited from being recorded in a specific recording layer among the plurality of the recording layers.

Abstract: A method and a transmitter (100) and a receiver (102) for transmitting messages (114) in a digital telecommunications system. The information (104) to be sent is encoded in an information encoder (106) of the transmitter (100) into frames that are transmitted via a transmission path (108) to the receiver (102). A good state and a bad state have been defined for the frames, and a bit pattern corresponding to each message (114) has been defined. The messages(114) are encoded with a message encoder (116) of the transmitter (100) and transmitted to the receiver (102). The messages (114) are transmitted together with the information (104) via a common transmission path (108), inserting the bit pattern corresponding to the message (114) in the frame, forming the frame corresponding to the time of transmitting the message (114) as bad, and in short sequences, preferably only one frame at a time.

Abstract: A hitless path switching ring network capable of switching from a work transmission line to a protection transmission line without instantaneous hitting of a signal when a failure occurs in the work transmission line. In the hitless path switching ring network, a node device includes a first memory section storing a signal being transmitted onto the work transmission line during normal operation, and a first read control section, at the time of failure occurrence, reading out the transmitted signal, held before failure occurrence, from the first memory section and sending out the transmitted signal through the protection transmission line in the opposite direction from the transmission direction employed before failure occurrence.

Abstract: A node representation system designates for one of a plurality of nodes for a master node and the rest for slave nodes. Each node refers to an address management table, and monitors the node of an entry next to each node in the table in order. As a result, each node monitors the node of the next entry, and simultaneously is monitored by the node of the preceding entry. When detecting a failure in a node to be monitored, a node represents the functions of the failed node, and further represents the monitoring of a node monitored by the node. When an instruction to duplicate the resource of the master node to each slave node is issued by a control node, the master node represents the functions of each slave node while duplicating.

Abstract: A method, system and article of manufacture to prevent signaling congestion in a connection-oriented network node in situations where a plurality of network-attached data terminal equipments (source DTEs) concurrently request a connection to at least one network-attached data terminal equipment (destination DTE), each of the source DTEs sending call setup messages (CSMs) through the network node to the at least one destination DTE. The CSMs having to be processed by the network to establish the connections requested.

Abstract: An advanced traffic shaper is provided for shaping real-time traffic in an IP-based network while simultaneously providing keep-alive bandwidth for best-effort traffic. The traffic shaper comprises a packet classifier coupled to receive an incoming packet from the network and to classify the incoming packet as one of a real-time packet and a best-effort packet; a packet discarding block coupled to perform traffic shaping of the incoming packet from the packet classifier and discard the incoming packet in accordance with traffic shaping parameters; connection queues coupled to temporary store real-time packets and best-effort packets from the packet discarding block, respectively; and a packet scheduling block coupled to send the real-time and best-effort packets from the connection queues to an outgoing device in accordance with the traffic shaping parameters.

Abstract: The present invention aims at providing an ascending transmission speed controlling method and a communication system in an ATM-PON (asynchronous transfer mode-passive optical network), in which ascending transmission speeds on the PON are dynamically allocated corresponding to actual transmission states of communication channels of a best effort type, to thereby effectively utilize respective bands.

Abstract: A method of controlling the route used for a flow in an environment comprising a default routing path and a shortcut path in an MPOA enabled ATM based network. A data field is added to the Ingress Cache table in the Ingress MPOA Client (I-MPC) to indicate whether the flow is to be routed through an MPOA shortcut towards the Egress MPOA Client (E-MPC) or is to be routed through the default path towards the Ingress MPOA Server (I-MPS). A first embodiment comprises a method of controlling the routing of a data flow from a source to a destination for security purposes. A second embodiment comprises a method of load sharing a plurality of data flows. A third embodiment comprises a method of learning about past MPOA resolution successes and failures and utilizing past establishment history to bypass the MPOA resolution process.

Abstract: An information cell transmission method includes receiving flow control cells at a switch from a collection of multicast virtual circuits and aggregating the flow control cells to form an aggregate flow control cell. A network switch includes first and second port circuitry and control circuitry. The first port circuitry is operative to exchange flow control cells on a collection of multicast virtual circuits coupling the switch to destination nodes. The second port circuitry is operative to exchange flow control cells on another virtual circuit that couples the switch to a source node. The control circuitry is operatively couples the collection of multicast virtual circuits to the source virtual circuit via the first and second port circuitry.

Abstract: The present invention provides a method and system for computing and storing minimum-cost routes to all destination nodes in a network. According to one embodiment, the present invention is applied in the context of computing quality of service routes using a source-directed connection-oriented routing environment. The route computation scheme employs an extension to Dijkstra's algorithm coupled with discretized link costs to generate a shortest-path graph with one or more routes to each destination. The present invention provides a compact data structure for storing at least one minimum-cost route to each destination node in a network. In particular, the routes are stored using a directed acyclic graph representing at least one minimum-cost pre-computed route for each destination node in the network. Each destination node in the network is associated with one or more parent pointers pointing to an upstream node in network that lies along a minimum-cost route.

Abstract: A system for determining the data rate capacity of a digital subscriber line includes a communication server coupled to a number of subscribers using twisted pair subscriber lines. A memory coupled to the communication server stores attenuation information and noise information for the twisted pair subscriber lines. A processor coupled to the memory determines the data rate capacity of a selected twisted pair subscriber line using the attenuation information and the noise information.

Abstract: A network-provisioning data generating method, by which manual data registration can be prevented so that correct network provisioning data can be collected and registered in real time, and a transmission device, which is constituted according to the generated network structure, are provided.

Abstract: A method for transmitting command and control information between at least two nodes of an IEEE 1394 based home entertainment network, includes dynamically generating a node navigation tree, transmitting the node navigation tree to a video display unit, receiving a node navigation input identifying a particular node in the node navigation tree, modifying a subset of the node navigation tree based on the node navigation input, transmitting the modified subset of the node navigation tree to the video display unit, generating a node function list including one or more functions pertaining to the identified node, transmitting the node function list to the video display unit, receiving a node function input corresponding to a particular node function in the node function list, and transmitting a command to the identified node based on the node function input.

Abstract: A method and a system for managing a TCAM table are disclosed. A new route is inserted into the TCAM table at an available location using an index. The new route is added into a Patricia tree organized by a mask length associated with the new route. Routes having common prefixes with the new route are searched for in Patricia trees organized by longer mask lengths and in Patricia trees organized by shorter mask lengths to locate a chain for the new route. The chain for the new route groups routes having common prefixes. The routes in the chain are sequenced in an order of longer prefix first such that a route at a top of the chain has a longest prefix. A swap of routes in the chain is performed to accommodate the new route and to maintain the longer prefix first order.

Abstract: A method and apparatus for auto-detection of ISDN BRI services available for use by terminal equipment is disclosed. This auto-detection provides a variety of simulated call activity stimuli to the ISDN switch peered with the terminal equipment, thus exercising secondary ISDN features such as call conferencing, call forward, call transfer, and X.25/D channel data transfer capability in a manner that can be detected by the terminal equipment. For instance, the call conferencing feature can be detected by having the terminal equipment place a call to it's own directory number using one B-channel, answering the call on the other B-channel, and then attempting to add a third party to this call. By evaluating the messages returned from the switch during the attempted third party addition, the auto-detection process can determine whether the call conferencing feature is available.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A communication spacecraft generates a plurality of spot beams having a given spatial relationship. Four beams of the plurality are used to maintain the antenna aligned with a ground station. The four beams are sequenced about the ground location, and the signal characteristics of each beam are used to maintain pointing. The sequencing requires continual switch operation, and failure to maintain antenna position, as might be occasioned by the failure of an element such as a switch or oscillator, is ameliorated by a redundant source of beacon signals, together with an arrangement which duplicates the beacon signal, and uses redundant switch cascades and combiners to perform the switching required for sequencing the beams.

Abstract: The present invention is a novel and improved method and apparatus for performing closed loop power control. A method of implementing reverse link outer loop using only pilot signal is described. Such a method is especially useful when the data signals are only present in short burst such that packet or frame error rates (PER or FER) cannot be estimated accurately. Moreover, since this method provides a mechanism for accurate set point adjustment even without a PER (FER) estimate, it can also be used to improve the accuracy of outer loop performance when such estimate becomes available. The present invention estimates a “pilot bit error rate” (PBER), where each pilot “bit” consists of a number pilot chips distributed over a frame. In addition, it estimates the normalized variance of the signal energy (or C/I) for each packet. In addition, in the preferred embodiment, the average number of fingers in lock is also used to determine the power control set point.

Abstract: A forward power controlling apparatus in a CDMA mobile communication system is provided. In the forward power controlling apparatus, an SIR measurer measures the SIR of each received frame on a forward user channel using all the demodulated symbols of the frame, a symbol rate detector detects symbol rate information inserted in a predetermined position of the frame, and a controller changes a threshold according to the detected symbol rate information, compares the threshold with the SIR, and generates a forward power control command.

Abstract: There is disclosed, for use in a CDMA wireless network, a base station capable of performing a soft handoff of a mobile station while the mobile station is still in the process of first accessing the wireless network. The base station comprises a receiver for receiving from the mobile station a system access message that initiates in the wireless network a system access procedure that establishes a communications channel between the mobile station and the CDMA-based wireless network. The base station also comprises a handoff controller, coupled to the receiver and receiving the system access message therefrom. The handoff controller prepares another selected base station in the CDMA-based wireless network to take control over the system access procedure by sending a handoff control message that initiates in the selected base station a handoff procedure capable of assuming control over the system access procedure.

Abstract: A system and method for correlating messages from A interface links is disclosed. When an initial connection message for a new call connection is detected, a new anchor record and call record are created to capture messages for that call. When an initial handover connection is detected, a handover pending record is created to collect messages related to the handover connection. When either a handover-from or handover-to connection is detected, a handover connection reference record is sent to a rendezvous processor. Handover-to and handover-from connection reference records are correlated in the rendezvous processor by matching data keyed to the specific handover event. Once a handover pending record is paired to an existing anchor record, the handover pending record is converted to a routing record to route messages to the anchor record.

Abstract: Even in a case where a using frequency differs for each region of a service area, a mobile direction of a mobile station M is determined by a mobile direction determination section 115 in a network side (control station), and whether or not the mobile station M moves out of the same frequency area is determined by a determination section 116 for an outer area of the same frequency, and the using frequency is changed in advance by a frequency change section 104 of the mobile station

Abstract: Circuitry combines a plurality of digital communication channels in a telecommunication system with reduced hardware requirements. The circuitry accumulates samples of the input communication channels in a register using an adder. The bit width of the connection lines between the register and the adder may be selected considering the bit width and number of input communication channels, such that minimal bit widths are provided.

Abstract: A channel access control device and method are provided in which a base station reserves a specific access slot for a mobile station when the mobile station has data to transmit which exceeds one frame in length. The base station receives channel access information from the mobile station via a reverse access channel; and examines a length of transmission data, included in the received channel access information, to determine whether the transmission data continues in at least one succeeding frame; and reserves a specific access slot on the reverse access channel for the mobile station via a forward access channel when the data continues in the at least one succeeding frame.

Abstract: A first group of terminals at a first range from base station is instructed, e.g., by transmitted timing advance values, to time their transmissions to arrive at a base station in synchronism with a first series of frames. A second group of terminals at a second range is instructed to time their transmissions to arrive at the base station in synchronism with a second series of frames that is time-offset with respect to the first series of frames. Transmissions from the first and second groups of terminals are, received at the base station in synchronism with the respective first and second series of frames. The transmissions from respective first and second groups may be received on respective separate carrier frequencies, or may be multiplexed on a common carrier frequency.

Abstract: A system and method are described for partitioning a network service among a plurality of service managers. The method includes configuring a first service manager to send a first request to a forwarding agent for packets meeting a first criteria and sending the first request to the forwarding agent. A second service manager is configured to send requests to the forwarding agent for packets meeting a second criteria and the second request is sent to the forwarding agent. Packets are checked at the forwarding agent to determine whether the packets meet the first criteria or the second criteria and packets that meet the first criteria are received at the first service manager; and packets that meet the second criteria are received at the second service manager.

Abstract: The present invention includes a method, system, and apparatus for providing communication control. The invention includes a method in which signaling is processed externally to a switch before it is applied by the network elements. The processor is able to select network characteristics and signal the network elements based the selections. A network employing the processing method is also included, as well as a signaling system that employs the processing method.

Abstract: Voice services provided over a packet switched facility such as a Frame Relay network are enhanced with routing capability by providing for attachment devices which, on initialization with the network, attempt to discover other similar attachment devices on the network. Thereafter the attachment devices exchange information on terminal accessibility to improve connectivity over the network.

Abstract: A content addressable memory (CAM) having a search field, a mask and an output for each CAM location is used to efficiently determine a processor for processing IP packets, with each IP packet being received as a sequence of cells. IP packets may be assigned to a processor (group) based on an examination of the header data, potentially including IP header and other higher layer protocols headers. The search field of a CAM location is pre-stored with header data, and the bit positions to be searched in the location are specified by using a mask. The output of the location identifies the processor group for executing packets with headers matching the search field, with only the bits specified by the mask being compared. When a first cell of an IP packet is received, the header data is provided as an input to the CAM, and the output identifies the processor (group) for executing the IP packet.

Abstract: This invention provides a communication network with a method and apparatus for interrupting the transmission of an existing stream of data to insert interrupting packets which may have a higher priority than the existing data stream. The interrupting packets are inserted in the data stream by making use of unused pointer values in common transmission schemes known as the Data Over Cable Service Interchange Specification (DOCSIS) or the Asynchronous Transfer Mode (ATM) adaptation layer 2 (AAL2) format of the International Telecommunications Union (ITU) recommendation I363.2. Advantageously, the scheduling of packets is significantly simplified and the packet jitter is better controlled which results in a significant improvement in transmission performance.

Abstract: An apparatus and associated method for performing flow switching (tag switching) in a frame switching environment. The flow switching apparatus provides a mechanism whereby flows are identified and tags assigned to them. The identification and assignment of tags to flows is made Independently of other network entities and does not require communications with any other entities within the box itself or other entities in the network. The forwarding decisions are calculated once and stored in a cache or a look up table which can be accessed very quickly. The tag is used as an index into the cache or LUT such that if an entry is found in the cache or LUT for that particular tag, the forwarding decision does not have to be made again. This serves to greatly reduce the time to obtain a forwarding decision which is used by the switching fabric in steering the input frame to the appropriate output port(s). Multiple queues are used along with the cache to facilitate the forwarding of the frames.

Abstract: A method, apparatus, and computer program product of interfacing a time-domain multiplexed (TDM) link with a cell-switched network. The TDM link supports one or more active channels and one or more idle channels and supplies TDM frames with a sample of each channel in a dedicated timeslot. The TDM link is terminated at a first network node. One or more idle timeslots are removed from each TDM frame to create a compressed TDM frame, where each idle timeslot carries a sample of an idle channel. One or more compressed TDM frames are loaded in a cell that is sent over the cell-switched network to a second network node. The compressed TDM frames are unloaded from the cell. Idle timeslots are inserted in the compressed TDM frames to restore the compressed TDM frames to complete TDM frames. The bandwidth of the cell switched network is efficiently utilized because idle channel samples are not carried over the cell-switched network.

Abstract: Multiple searches of a filtering database increase the time for filtering a data packet received by a switch. A switch including a translator and a filtering database for performing a single search is presented. The translator provides a translated identifier for an identifier associated with a data packet received by the switch. The translated identifier includes a group identifier corresponding to a virtual LAN group (FID) and a group member number corresponding to an identified virtual LAN (VID). The filter data base stores a static entry and a dynamic entry. The static entry stores a forwarding decision for the data packet associated with the translated identifier. The dynamic entry stores a forwarding decision for the data packet associated with the group identifier included in the translated identifier and the group member number set to don't care.

Abstract: A two-dimensional round-robin scheduling method with multiple selection is provided. The two-dimensional round-robin scheduling method in accordance with an embodiment of the present invention includes following steps. First step is for checking whether a request is received from the input buffer module and building mxm request matrix r(i,j), i,j=1, . . . , m. Second step is for setting mxm search pattern matrix, d(i,j), i,j=1, . . . , m. The search pattern matrix describes search sequence, S=1, . . . , m. Third step is for initializing elements of mxm allocation matrix a(i,j), i,j=1, . . . , m. The allocation matrix contains information whether transmission request is accepted and which switching plane the accepted request uses in transmission. Fourth step is for examining a request matrix in accordance with the search sequence S and finding r(i,j) that sent a request.

Abstract: There is disclosed, for use in an asynchronous transfer mode (ATM) network, an ATM switch controller capable of routing a call through the ATM network. The ATM switch controller comprises: 1) a database capable of storing at least one of quality of service (QoS) data and congestion level data received from a plurality of ATM switches in the ATM network; and 2) a route selection controller capable of receiving a call request from a first of the plurality of ATM switches and selecting a call route connection to a second of the plurality of ATM switches, wherein the second ATM switch adjoins the first ATM switch and the selected call route connection is selected in response to at least one of QoS data and congestion level data of the second ATM switch stored in the database.

Abstract: An improved method, system, and computer program product for efficient transmission of data to multiple network nodes is disclosed. A method for transmitting a data block over a network from a first sending node to a first set of recipient nodes, comprises, in the first sending node, a) dividing the first set of recipient nodes into a subset of selected nodes, selected according to scoring criteria associated with each recipient node, and a subset of unselected nodes, b) assigning at least one of the unselected nodes to at least one selected node according to scoring criteria associated with the respective selected nodes, c) transmitting to each selected node a packet including the data block and a list of the nodes assigned to the selected node.

Abstract: A method serves to compose a VPN (Virtual Private Network) over a plurality networks each of which is managed by different Internet Service Providers (ISP). When a packet with a first capsule header used for composing a VPN in a first ISP network is transmitted to a second ISP network, a route for outputting packet to the second ISP network is determined based on the information both in the capsule header and in the IP header. In addition, a second capsule header used for composing a VPN in the second ISP network is determined based on the above information.

Abstract: An Ethernet ADSL adapter controls data communication between an Ethernet port and an ADSL modem connected to an ADSL channel. The adapter includes a first buffer for storing data packets received at the Ethernet port, a second buffer for storing data packets received from the ADSL modem and a controller. When the first buffer contains a first predetermined number of data packets and data packets are not available for transmission to the Ethernet port, a jamming signal is transmitted from the Ethernet port. The jamming signal inhibits transmission of additional data packets to the Ethernet port by other Ethernet nodes until space is available in the first buffer. When the second buffer contains a second predetermined number of data packets, a pause signal is transmitted to the ADSL modem. The pause signal inhibits further transmission of data packets to the ADSL modem on the ADSL channel until space is available in the second+ buffer.

Abstract: A method and apparatus for generating massive interrupts in random access memory (RAM) are provided, comprising receiving and storing Time Slot network (TS Net) data frames comprising switching event information in a first RAM area. Compare operations are performed among prespecified ones of the TS Net data frames. Unit interrupt bits are set in a corresponding location of a second RAM area in response to detected bit differences resulting from the compare operations. Interrupt status bits are set in a corresponding location of a third RAM area in response to set unit interrupt bits. Massive interrupt signals are generated in response to set unit interrupt bit.