Patents Examined by H. Kizou
  • Patent number: 5107492
    Abstract: Method and device for managing access to the transmission medium of a multiservice distributed switching network adapted to switch traffic in synchronous circuit-switched mode and in synchronous or asynchronous packet-switched mode, the architecture of the network being based on a transmission medium time-shared between different stations characterized in that: (1) the transmission medium is synchronous and structured in frames in turn structured in time slots in turn structured in time cells, the latter being sized to contain a communication entity which can be either a circuit-switched cell or a segmented packet-switched cell, (2) an ideal time slot for access to the transmission medium in packet-switched mode is assigned to the respective stations communicating within the network, and (3) in each time cell and for all stations transmission medium access arbitration is applied to procure priority access to this medium for circuit-switched cells available at this time in any station.
    Type: Grant
    Filed: June 19, 1990
    Date of Patent: April 21, 1992
    Assignee: Alcatel Business Systems
    Inventors: Raphael Roux, Ji-Yong Wu
  • Patent number: 5103445
    Abstract: A method in a mobile radio communication system for adapting the system and communication to prevailing traffic and performance requirement. According to the invention a mobile station inserts information on particular codes in its messages transmitted to a base station in response to an invitation message from the base station. The codes indicate whether a message is new or retransmitted and/or message age. The base station receives radio signals in time slots identified in its invitation message and estimates for each time slot based on radio signals received in the time slot whether the time slot is empty or busy, or whether the time slot is empty or correct. For each message received and understood the base station retrieves the code. The retrieved codes and the number of empty/busy/correct slots enable the base station to estimate prevailing system traffic and performance.
    Type: Grant
    Filed: July 31, 1990
    Date of Patent: April 7, 1992
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventor: Anders K. Ostlund
  • Patent number: 5103447
    Abstract: A high-speed ring LAN capable of accommodating at least one public network having a signal transmission rate of 155.57 MHz, and at least one sub-LAN having a signal transmission rate of 100 MHz. The high-speed LAN has a signal transmission rate of 155.52 Mbps.times.n (n is an even number). SONET (Synchronous Optical NETwork) subframes each comprising a 9 bytes.times.9 section overhead area and a 261 bytes.times.9 virtual container 4 (VC-4) area flow in a time-divisional n-multiplexed format. The respective node devices inserted in the transmission path have one or more ports to accommodate sub-LANs or public networks. Information is exchanged in units of a fixed-length packet between a received SONET subframe and an asynchronous packet whereas information is exchanged in units of a byte between the SONET subframe and a synchronous port.
    Type: Grant
    Filed: August 29, 1989
    Date of Patent: April 7, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Takiyasu, Toshiki Tanaka, Taihei Suzuki, Eiichi Amada, Yukiji Yamauchi, Mitsuhiro Yamaga, Matsuaki Terada, Kunio Hiyama
  • Patent number: 5101401
    Abstract: In order to judge whether a received digital signal has a true polarity or an inverted polarity, a polarity judging arrangement comprises first and second synchronization word detecting circuits for detecting, from the received digital signal, first and second predetermined synchronization words for multiframe and frame synchronization signals, respectively. The second predetermined synchronization word is defined by inverting the first predetermined synchronization word. Each multiframe has at least two frame synchronization signals. A counting circuit has an initial value and counts down and up a count in response to first and second detection pulses produced by the first and the second synchronization word detecting circuits, respectively. The counting circuit produces first and second judgement result signals representative of the true and the inverted polarities when the count increases up to an upper threshold value and when the count decreases down to a lower threshold value, respectively.
    Type: Grant
    Filed: November 29, 1990
    Date of Patent: March 31, 1992
    Assignee: NEC Corporation
    Inventors: Toshio Suzuki, Kenji Kanetake
  • Patent number: 5099475
    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.
    Type: Grant
    Filed: August 9, 1990
    Date of Patent: March 24, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Takahiko Kozaki, Noboru Endo, Yoshito Sakurai
  • Patent number: 5086427
    Abstract: A system wherein multiple sources of data each have drivers for transmitting data to a common system bus. The drivers are each managed by individual enabling logic which is controlled by a flip-flop driven by a clock. Thus no driver can connect and drive data onto the bus until one clock period after the previously connected driver has been disabled and disconnected from the bus.
    Type: Grant
    Filed: April 9, 1990
    Date of Patent: February 4, 1992
    Assignee: Unisys Corporation
    Inventors: Bruce E. Whittaker, Saul Barajas, Leland E. Watson
  • Patent number: 5079762
    Abstract: In an asynchronous transfer mode switching system, the logical channel number contained in a cell from a user station is translated in an associated one of line circuits to an assigned logical channel number. A self-routing network reads successive bits of the assigned logical channel number of the cell as it propagates through the network to a desired one of cell buffers. A controller receives user information from the line circuits and determines the assigned logical channel number. A waiting buffer is connected from one of the network's outgoing line terminals to one of its incoming line terminals. If the storage level of the cell buffer which is desired by the cell is higher than a predetermined level and if the cell belongs to a class demanding a high grade of service, the controller changes the assigned logical channel number so that the cell is routed from the line circuit through the network to the waiting buffer.
    Type: Grant
    Filed: September 28, 1990
    Date of Patent: January 7, 1992
    Assignee: NEC Corporation
    Inventor: Sen'ichi Tanabe
  • Patent number: 5079768
    Abstract: A frequency-hopping packet communication system without a master clock or master control unit is based on use of a receiver's frequency hopping timing and identification to control communication. A frequency-hopping band plan, involving the number of channels and the pseudo-random pattern of frequency change and nominal timing of changes, is universally known to each node in the network. Frequency-hopping is implemented by the division of communication slots and the accumulation of slots into epochs, wherein each epoch equals the total number of available slots (number of channels times the number of time frames per channel). A transmitting node tracks the preestablished frequency-hopping pattern for its target receiver based on previously-acquired information. The transmission node identifies a receiver node and a current frequency channel of such receiver node. The transmission node then checks the frequency channel to determine if available (e.g., not in use and within an acceptable noise margin).
    Type: Grant
    Filed: September 11, 1990
    Date of Patent: January 7, 1992
    Assignee: Metricom, Inc.
    Inventor: George H. Flammer
  • Patent number: 5079765
    Abstract: A network system includes a local area network to which a plurality of transmission apparatuses are connected, a gateway apparatus for connecting the local area network to a wide area network, and a plurlaity of terminal adapters for connecting the local area network to communication terminal apparatuses, and a management method therefor. Each transmission apparatus sends a transmission request of management data requesting data on the operating conditions of the connected local area network, the gateway apparatus, and the terminal adapters, acquires data on the operating conditions of the other apparatuses sent in response to the transmission request, and simultaneously displays the acquired management data, so that the operating conditions of the apparatuses connected to the system can always be monitored. Even when a communication error occurs, location of the source of the error can be easily determined without arranging a special-purpose LAN monitoring apparatus.
    Type: Grant
    Filed: January 3, 1990
    Date of Patent: January 7, 1992
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yasuo Nakamura
  • Patent number: 5077730
    Abstract: A method and apparatus of releasing resources allocated to terminated sessions at a secondary data processing node. A first node transmits one or more switch messages to a second node requesting the second node to redistribute sessions on a first route between the nodes among one or more alternate routes. Each switch message identifies the sessions to be switched and an alternate route to which the sessions are to be switched. The last switch message transmitted by the first node is indicated to be the last message in some appropriate way and includes a count of the total number of sessions that have been requested to be switched. The second node accumulates a count of the total number of sessions on the first route for which it has received a switch request. The second node compares its accumulated count with the total count derived from the last switch message and releases the resources allocated to all remaining sessions on the first route in the event the counts are equal.
    Type: Grant
    Filed: August 2, 1990
    Date of Patent: December 31, 1991
    Inventors: Andrew H. Arrowood, Kaiwah Chan, Owen H. Choi, John G. Dudley, Diane A. Schuster
  • Patent number: 5072440
    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.
    Type: Grant
    Filed: February 26, 1990
    Date of Patent: December 10, 1991
    Assignee: Fujitsu Limited
    Inventors: Osamu Isono, Toshimasa Fukui, Tetsuo Nishino, Tetsuo Tachibana, Ryuji Hyodo, Eisuke Iwabuchi
  • Patent number: 5065395
    Abstract: Rudimentary digital speech interpolation apparatus for compressing data on a plurality of channels is disclosed, which includes circuitry for receiving data bits and control bits for each channel. The presence of silence on each channel is determined in response to the received data bits and zero bits are allocated for any silent channel in a frame structure. In addition, circuitry also allocates x bits per channel for the data bits in an non-silent channel in the frame. At least six bits per channel are also allocated for the control bits in the frame. 4N such frames are grouped to form a multi-frame.
    Type: Grant
    Filed: April 9, 1990
    Date of Patent: November 12, 1991
    Assignee: DSC Communications Corporation
    Inventors: Kishan Shenoi, Patrick L. Hanagan, Helena S. Ho, Frank I. Yu
  • Patent number: 5060226
    Abstract: A telecommunications line test system wherein a digital telecommunications network is electronically sectionalized via at least one master test unit in combination with at least one remotely addressable field loopback unit whereby the defective line section is isolated by progressively looping back test data as transmitted from a master test unit. Each field loopback unit, when properly addressed, will loopback to both the near side and the far side of the line so as to enable a given loopback unit to be reset (inactivated) from either side of the line.
    Type: Grant
    Filed: July 5, 1990
    Date of Patent: October 22, 1991
    Assignee: Phoenix Microsystems, Inc.
    Inventors: Robert E. Gewin, Gary L. Aderholt
  • Patent number: 5058105
    Abstract: A facility is provided for enhancing the reliability of a communications network so that traffic whose flow is disrupted by, for example, a faulty link, may be quickly restored to service. In particular, such traffic is restored to service by establishing a number of orders of connectivity each formed from spare link capacity, in which each succeeding order of connectivity represents the shortest loop around a preceding order of connectivity.
    Type: Grant
    Filed: April 4, 1990
    Date of Patent: October 15, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: M. Omar Mansour, Liem T. Nguyen
  • Patent number: 5051993
    Abstract: A communication system has an information signal having a plurality of data streams. The data streams are simultaneously modulated on a multi-level symbol transmission. The data streams may have either independent or dependent signalling protocols. A transmitting device generates the information in one of several embodiments. A first receiver receives the information signal and process only a first data stream for messages. A second receiver receives the information signal and process only the second data stream for meassages. A third receiver is capable of selectively receiving and processing a plurality of data streams. The third receiver is shown in several embodiments for selecting the data streams.
    Type: Grant
    Filed: March 30, 1989
    Date of Patent: September 24, 1991
    Assignee: Motorola, Inc.
    Inventors: Michael J. DeLuca, David F. Willard, Robert J. Schwendeman
  • Patent number: 5051982
    Abstract: Methods and apparatus are set forth for quickly making switched virtual connections (SVCs) in a digital circuit switch that integrates voice and data using common switch, control and distribution equipment. SVCs provide concurrent data connection service from one station device, such as a PC, to other station devices over a single line for each station device where the line may also carry voice and terminal data service. A switch control processor remembers connection requests from station devices and acts on opportunities to utilize available bandwidth in an optimal manner. Dynamic connection reconfiguration techniques allow the system to "scavenge" bandwidth unused by voice or terminal data traffic for SVCs thereby providing the largest possible data rate at any given time. Short signalling messages and indexed values are used in order to speed activation time for previously defined connections while resource allocation is performed by the switch control processor to further enhance system operating speed.
    Type: Grant
    Filed: July 27, 1989
    Date of Patent: September 24, 1991
    Assignee: Data General Corporation
    Inventors: David K. Brown, Richard L. Christensen
  • Patent number: 5051992
    Abstract: There is a communication system comprising: an integrated services digital network (ISDN) having a plurality of information channels (Bch) and at least one control channel (Dch); a CPU (host computer) connected to said ISDN through a communication control processor (CCP); and a plurality of packet terminals connected to the ISDN. In the communication system, when a call request from the CPU or an incoming call request from one of the packet terminals is input to the CCP, if the B channel data link connection or the D channel data link connection for the packets has already been established between the CCP and the ISDN, the CCP selects the channel data link connection as a channel for communication with the packet terminal and multiplexes a plurality of calls to the same channel even if the other space B channels exist.
    Type: Grant
    Filed: November 8, 1989
    Date of Patent: September 24, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Hidenobu Taniguchi, Satoshi Miyazaki, Sinichi Kouyama, Tatsuo Kawatobi, Keizou Mizuguchi, Kazuo Yagyu
  • Patent number: 5051979
    Abstract: Errorless switching of digital signals from a service channel is achieved even to an alternate channel, when the signals have a format in which the payload can float within the frame or in which the overhead bytes of the service channel may be different from the overhead bytes of the alternate channel. A preprovisioned delay is provided on the service channel. The amount of delay between corresponding frames containing the same payloads in the digital signals being transported in each channel is measured and added on the alternate channel, thus aligning the channels. The payloads within corresponding frames in the digital signals being transported in each channel are aligned by passing a pointer value indicating the start of the payload of the signal being transported in the service channel to the alternate channel and shifting the payload of the signal being transported in the alternate channel in accordance with the passed pointer value.
    Type: Grant
    Filed: June 28, 1990
    Date of Patent: September 24, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: S. Chaudhuri, A. Maione
  • Patent number: 5048011
    Abstract: A fast packet switching system has an interconnection network associated with a distributed control structure composed of a plurality of processing units (UC1-1 . . . UC3-16) managing the routing at the virtual call level. At least some processing units each associated with a group of network inputs/outputs store bandwidth occupancy data relevant to the interstage links which can be reached from the inputs of the group and are included between the inputs and a central network stage where there is a maximum number of alternative paths or, respectively, bandwidth occupancy data relevant to interstage links which lead to the outputs of the group and are included between the stage and the output, the data being updated whenever a new call is routed.
    Type: Grant
    Filed: April 14, 1989
    Date of Patent: September 10, 1991
    Assignee: CSELT - Centro Studi E Laboratori Telecomunicazioni S.p.A.
    Inventor: Riccardo Melen
  • Patent number: 5043981
    Abstract: An FDDI system and method for transmitting to an optical medium, upon receipt of token, frames of synchronous data and frames of asynchronous data having different levels of priority. The network on which the FDDI is implemented includes a plurality of processors each having a system for storing the frames of data in queues corresponding to priority, and an output buffer configured to have a plurality of logical FIFOs corresponding to the queues. Data is transferred one queue at a time from the system memory to the output buffer through a single physical FIFO. To prevent the FIFO from "locking-up" as a result of any residual data remaining therein following each transfer of a frame to the output buffer, storage remaining available for a particular queue of the output buffer to be transmitted to the medium is detected. Data is transferred from the system memory to the FIFO memory only if the storage remaining available is at least equal to the storage capacity of the FIFO memory.
    Type: Grant
    Filed: May 29, 1990
    Date of Patent: August 27, 1991
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Farzin Firoozmand, Brian Childers