Abstract: A method and system are disclosed for enabling point-to-point and multicast communication in a network using three types of communication channels, namely, one or more upstream payload channels, one or more upstream control channels and one or more downstream channels. At least the upstream control and upstream payload channels can carry bitstreams simultaneously; a bitstream may be simultaneously carried on the upstream control and upstream payload channels of a shared medium during overlapping periods of time. Each channel illustratively is divided into slots or mini-slots. Each upstream payload channel is assigned for carrying upstream directed payload bitstreams from stations to a central controller. Each upstream control channel is assigned for carrying upstream directed control bitstreams, such as reservation request bitstreams requesting reservation of time slots of the upstream payload channel, from the stations to the central controller.

Abstract: Data transmission by a half-duplex transceiver over a full-duplex cellular telephone system using the EIA/TIA-553 standard is achieved by monitoring the forward channel to synchronize the transceiver with the forward channel signal, switching to transmit mode to transmit data on the reverse channel, and momentarily switching back to receive mode during the transmission at the projected times of occurrence of significant status bits on the forward channel in order to detect status bits whose timing controls operation of the transceiver.

Abstract: An asymmetric network communication system for use in a client-server environment having independent forward and return channels operating at different speeds and/or under different protocols on the same or different communication media to provide efficient utilization of shared resources. A network manager, such as a hybrid access system, effects transmission of packetized data on a forward (downstream) channel from the host server to multiple client devices coupled with a shared downstream media at 10 or more megabits per second while simultaneously providing selectable multiple lower speeds of operation on shared or dedicated return (upstream) channels from the client devices to the host server depending on bandwidth availability, bandwidth demand, service level authorization, etc. for the return channel.

Abstract: The present invention enables a dial modem capable of simultaneous voice and data (SVD) operation and connected to a conventional telephone set to automatically select between SVD operation, analog voice operation and digital data operation when transmitting or receiving communication signals based on the position of the telephone set's hookswitch. The invention includes a hookswitch position detector, connected to the telephone set, for sensing the current position of the hookswitch, and a signal controller, connected to the hookswitch position detector. The signal controller may be configured to enable either of two hookswitch control option settings. The hookswitch control option settings determine the manner in which the controller responds to the current hookswitch position ("on-hook" or "off-hook") detected by the hookswitch position detector.

Abstract: A measuring device for the interface of a transmission path with full-duplex transmission in the common carrier duplex process. A highly integrated interface unit is connected to the interface via a hybrid set and a transmitter on one side. A line termination or a network termination is connected as the test object on the other side. In order to perform measurements on the test object with such a measuring device relatively easily and accurately, a device simulating the arrangement of a hybrid set, a transmitter and a line or network termination is provided and with its connected to the highly integrated interface unit via a high-resistance differential amplifier, and its output connected to an input of a subtractor. Another input of the subtractor is connected to the interface via an additional differential amplifier. The output of the subtractor is connected to a measurement system.

Abstract: A transceiver (5) for an asymmetric communication system such as asymmetric digital subscriber line (ADSL) includes a configuration register (71) defining operation at either a central office (CO) or a remote terminal (RT). The configuration register (71) includes a control bit (72) for selecting either CO or RT mode. The transceiver (5) includes a signal processing module (70) configured according to the state of the control bit (72). For example, a digital interface (70) converts transmit data into transmit symbols and converts received symbols into receive data. The digital interface (70) uses a large memory (158) as a buffer in the transmit path and a small memory (160) as a buffer in the receive path in CO mode. In RT mode, the digital interface (70) uses the small memory (160) in the transmit path and the large memory (158) in the receive path. The selective configuration allows a single integrated circuit to be used in both CO and RT equipment.

Abstract: A full duplex communication circuit uses a transducer as both a microphone and speaker/earphone to provide full duplex communication without acoustical feedback. The circuit uses a novel amplifier configuration to apply a signal received from a remote source to the transducer without loading it. The output of the transducer has a combined transmit and receive signal. To eliminate feedback of the receive signal in the output of the transmit signal, an audio processing circuit (analog) takes this combined signal and simultaneously compresses the receive signal and expands the transmit signal to produce a transmit signal that is 35-40 dB greater than the receive signal at the output.

Abstract: A method and apparatus for providing full duplex asynchronous communication between two transceivers in a communication system is disclosed. First each bit period is divided in half creating a transmit half bit period and a receive half bit period wherein each transceiver can transmit data during the transmit half bit periods and can receive data during the receive half bit periods. The bit periods of the two transceivers are synchronized so that the transmit half bit periods of each transceiver are aligned with the receive half bit periods of the other transceiver.

Abstract: Signal area efficiency in integrated circuit designs is improved by increasing the information efficiency of signal wiring on an integrated circuit. Candidate signals are selected for combination by prioritizing signals according to length of travel, travel path, and information content. Signals with low information content and with greater distance between endpoints make poor utilization of fixed wiring and provide the best candidates for improvement. Candidate signals which travel similar (substantially parallel) paths from point to point across the integrated circuit are combined to improve chip area utilization efficiency. A variety of techniques are described for combining low-information-content signals onto a small number of wires, transmitting them over the small number of wires, and re-expanding them at their destination. Assuming that the combining/expanding circuitry occupies less space than the point-to-point wiring which would otherwise be required, there is a net reduction in chip area.

Abstract: A duplexer having dual coupled line characteristics is disclosed. With a small number of resonators and without using an external device such as a chip inductor or a chip capacitor, the signals of the receiving frequency can be improvingly damped. The diameters of the transmitting terminal dielectric filter resonators and the receiving terminal dielectric filter resonators are not same, but their diameters at an open terminal and at a short circuit terminal are made different from each other so as to differentiate a coupling amount at the short circuit terminal from that at the open terminal. Further, the transmitting terminal filter resonators and the receiving terminal dielectric filter resonator are provided in a form of grooves, and sizes of the grooves near the open terminal are made different from those of the grooves near the short circuit terminal so as to differentiate a coupling amount of the resonators at the short circuit terminal from those at the open terminal.

Abstract: A transceiver for exchanging data with a transmission channel using any of the 100BaseT2, 100BaseTX, or 100BaseT4 standards, which includes a receive circuit for receiving analog data from the transmission channel. The receive circuit includes a first switch and a first analog-to-digital converter coupled to the first switch. The receive circuit further includes a second analog-to-digital converter coupled to the first switch. There is further included a second switch coupled to the first analog-to-digital converter and to the second analog-to-digital converter. The analog data is switched by the first switch into the first analog-to-digital converter and the second analog-to-digital converter to allow the first analog-to-digital converter and the second analog-to-digital converter to support sampling requirements of any of the 100BaseT2, the 100BaseTX, or the 100BaseT4 standards.

Abstract: A pulse density signaling input/output (PDSIO) scheme is implemented to provide a two-way, two-wire hybrid analog/digital communications system. PDSIO signals are sent as logic pulses from a "master" port to one or more "slave" ports over a twisted pair. From one to a predetermined maximum number of logic pulses are transmitted over two wires at baseband by a master port during a defined period. The modulation used by the master port is pulse density modulation at base band so that the transmitted signal appears to be a d.c. logic signal. The pulses transmitted to the slave port are also used to power the slave port. The slave port communicates with the master port over the same two wires using a pulsed current modulation that multiplexes data on the pulse signals from the master port.

Abstract: A performance monitor system monitors a number of errors occurring in data processed in a communication apparatus having a duplex configuration formed of two systems. The performance monitor system includes a first unit for monitoring a number of errors occurring in data processed in one of the two systems a second unit for monitoring a number of errors occurring in data processed in another one of the two systems and a control unit for controlling operations of the first and second units. Each of the first and second units has a first counter outputting a first error count value and a second counter outputting a second error count value. The control unit controls the first and second counters so that the sum of the first and second error count values obtained in the first unit is equal to sum of those obtained in the second unit.

Abstract: A single-chip video compression/decompression (video codec) chip is connected to receive a video input from a NTSC-compatible or PAL-compatible camera and a transmit channel. Video information from the camera or other video input source is compressed by the video codec and transmitted out in compressed form on a transmit channel. Concurrently, compressed video information is input to the video codec from a receive channel, decompressed and output to the monitor or other video output device, e.g., a television set. Only a separate single module of dynamic random access memory (DRAM) is needed to provide storage for incoming and outgoing video data, compressed bit streams and reconstructed pictures for both compression and decompression procedures. The compression of video information is by spatial decorrelation of the intraframe information, and temporal decorrelation of the interframe information. The communication channel bit rate is further reduced by quantization and variable length coding.

Abstract: The present invention is a novel apparatus for amplifying upstream and downstream signals, the signals comprising different portions of a communications spectrum and wherein at least two portions require amplification in opposing upstream and downstream directions.

Abstract: A communication system comprises a master station 21 and a plurality of slave stations 22-1 to 22-N each of which communicates with the master station through a radio channel carrying a communication signal by using time division multiple access. The slave stations are similar in structure to one another. The master station is similar in structure to each of slave stations. Each of the slave stations selectively transmits a speech signal and an image signal to the master station. On transmitting the speech signal, the speech signal is converted into an ADPCM signal. On transmitting the image signal, the image signal is converted into a PCM signal. The master station receives the communication signal which is transmitted from each of the slave stations. The master station detects whether or not the communication signal is representative of the ADPCM signal to selectively produce the speech signal and the image signal.

Abstract: A method and approach for providing improved performance in a CSMA/CD-type network utilizing transmission of block encoded congestion sense signaling to allow full duplex transmission of data over a communication link segment. In addition, the method and apparatus for providing in-band signaling of congestion conditions is described. The improved method and apparatus are implemented with minimal changes to existing standards and allow for compatibility, above the MAC sublayer, with existing installed hardware and software bases.

Abstract: An apparatus and method for a data communications device, such as a modem (100, 101), to determine a symbol rate and carrier frequency combination, from a received probe signal, for optimizing a bit rate for data transmission and reception. The various embodiments utilizing a processor (108) or a digital signal processor (106) receive a probe signal, which also typically contains noise and other distortions. The various method and apparatus embodiments then determine signal to distortion ratios for a plurality of symbol rate and carrier frequency combinations (820), and other optimization parameters, such as channel characteristics and attenuation distortion parameters (830). These optimization parameters are then utilized to determine an optimal symbol rate and carrier frequency (840).

Abstract: An optical modem link for full duplex transmission of multiple, independent RF carrier signals between network elements of a Broadband Access Network, includes a first optical modem, e.g., at a CATV headend broadcast facility, linked by a single optical fiber with a second optical modem, e.g., at a distributed hub location, to form an optical modem link. Each optical modem end of a respective link is equipped with an optical transmitter, which transmits light signal having a first wavelength, a receiver which receives a light signal having a second wavelength, and a wavelength division multiplexer which directs the outgoing light signal onto, and the incoming light signal off of, respectively, the fiber link.

Abstract: A method and apparatus for playing the same video game by a number of players at remote locations over a telephone network. More specifically, a video representation of the game played by a number of video game players stored at each of the player locations. The control signals representing the actions of the players are then transmitted to a single one of the locations where the control signals are sequenced. The sequence control signals are then stored in a queue wherein the video game is played at each of the locations by synchronously reading the control signals from each queue at each of the locations and sending them to corresponding ports of each video game at each location.

Abstract: A communications system comprising a central unit (200) and a number of remote units (300) and a downlink (10) for communication from the central unit to the remote units and an uplink (11) for communication from the remote units to the central unit. A signalling channel is provided on the downlink, a plurality of traffic channels are provided on the uplink and signalling information is transmitted on the downlink signalling channel to indicate positively which of one or more of the uplink traffic channels is to be used as a signalling channel for a random access request.

Abstract: A flow control enabled Ethernet switch that applies backpressure to input ports that attempt to transmit a data packet to a busy destination port. The backpressure is a phantom packet that activates to abort transmission of the data packet. When the destination port is available, the phantom packets control retransmission, permitting standard retransmission of the data packet. The switch may include prioritization mechanisms to use when awarding priority to a port having backpressure applied.

Abstract: In a switching system and method in a multiplexed system, the multiplexed system is kept in continuous normal operation by duplexing of functions and by switching to a non-failure side when the multiplexed system partially fails. The system includes control registers for storing and generating control information on both sides, and state registers for storing and generating information on the defective location and the cause of the defect. With the information in the control registers, the system checks for trouble, and switches to a non-faulty side when trouble is detected. With the information in the state registers, the cause of the trouble is analyzed and stored.

Abstract: A communications system employs a high-speed digital link with discrete multiple tone (DMT) the outward paths from a central transmitter/receiver to further transmitter/receivers receiving signals therefrom using one set of carrier frequency channels and the return signal paths using a different set of carrier frequency channels.In one form the central transmitter/receiver is an exchange and the further transmitter/receivers are subscribers connected to the exchange.

Abstract: A bidirectional communication system for communicating signals between a master device (1) and a slave device (2) connected by a single wire (3), in which the master device (1) includes a voltage signal generator (4) for generating voltage signals to be transmitted to the slave device (2) over the wire (3), a current sensor (6) for sensing current consumed on the wire (3), and a received signal generator (14, 19) for generating received signals corresponding to the sensed current consumption. The slave device (2) includes a receiver (7) for receiving the voltage signals transmitted over the wire and producing received data therefrom, and a current consuming device (8) for consuming current from the wire (3) in correspondence with a signal to be transmitted to the master device (1).

Abstract: A system for full duplex real time two-way voice and data communication between a pair of computer terminal locations is disclosed. Analog voice signals are converted to digital form at one terminal location and those digital signals are interleaved with other digital information for transmission to the other terminal location. A value for the number of bytes, in a data packet is first established, and then values for the number of bytes and the location dedicated to the transmission of voice information, control information, and data transmission within such fixed size data packets is established. Thereafter, a sequence of data packets with synchronization bytes in the voice byte locations is transmitted from each computer terminal location and received by the other of the terminal location. Upon receipt thereof, an acknowledgement of the receipt is transmitted back to the originating location to indicate the establishment of synchronization between the two locations.

Abstract: A network transmitter device and network receiver device is described. The network transmitter device transmits a first voltage potential, a second voltage potential, a third voltage potential and a fourth voltage potential over a first pair of output lines and a second pair of output lines in response to digital signals received over a data input. The network receiver device receives network signals of a first voltage potential, a second voltage potential, a third voltage potential, a fourth voltage potential and a fifth voltage potential over a first pair of output lines and a second pair of output lines. The network receiver device transmits digital signals corresponding to the network signals.

Abstract: In a device for the serial exchange of data between two stations, each station has a serial interface which is connected to a common data transmission line. A first specific station has means which, during the reception of data, identify the two possible bit states on the basis of different voltage levels on the data transmission line. In contrast, the second specific station has means which, during the reception of data, identify the two possible bit states on the basis of the presence or absence of a specific current flow via the data transmission line. Furthermore, in another device for the serial exchange of data between two stations, suitable selection of resistors ensures that four different voltage levels are produced on the data transmission line when each station transmits a "1" bit state or a "0" bit state. The voltage levels are evaluated differently by the stations, with the result that simultaneous data transmission in both directions is also possible.

Abstract: A system for noise canceling using a single return conductor. The system employs a first unit, a full duplex communications path coupled to the first unit, and a second unit coupled to the first unit via the full duplex communications path. The full duplex communications path employs at least three conductors: a forward signal carrying conductor; a reverse signal carrying conductor; and a single return conductor. In order to perform noise canceling, the first unit may employ, for example, a first adder coupled to the reverse signal carrying conductor, and a first canceling impedance coupled between the single return conductor and a first unit ground. Similarly, the second unit 12 may employ a second adder coupled to the forward signal carrying conductor, and a second canceling impedance coupled between the single return conductor and a second unit ground.

Abstract: A method of managing communication on an unstable error-prone channel is disclosed, having particular applicability to transceiver nodes in a high frequency radio network. The method achieves highly reliable, efficient communication through the exchange of headers within control frames in accordance with a selected suite of protocols. An orderly link establishment is achieved by the exchange of headers indicating specific link establishment states of the nodes. One node having message data to transmit to another sends a herald header, and if the data is to be accepted by the other node, it responds with a herald acknowledgment header. The herald conveys parameters of the proposed transmission to the receiving node, permitting the parameters to be varied by the transmitting node for changing channel conditions. The issuance of a herald acknowledgment depends on message priorities exchanged by the nodes, so that higher priority messages can preempt lower priority ones.

Abstract: An apparatus and method for fast changeover in a duplex system are disclosed. The apparatus and method enhance a processing speed, by verifying the state of a pair side by using an interrupt method, and simultaneously, by separating a control register and a state register so as to verify a fail position and content, and change over exactly according to a position of a unit to be changed over and to fail state information by including a group/unit address and the fail state information in a control register and a state register.

Abstract: An asymmetric network communication system for use in a client-server environment having independent forward and return channels operating at different speeds and/or under different protocols on the same or different communication media to provide efficient utilization of shared resources. A network manager, such as a hybrid access system, effects transmission of packetized data on a forward (downstream) channel from the host server to multiple client devices coupled with a shared downstream media at 10 or more megabits per second while simultaneously providing selectable multiple lower speeds of operation on shared or dedicated return (upstream) channels from the client devices to the host server depending on bandwidth availability, bandwidth demand, service level authorization, etc. for the return channel.

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.

Abstract: A ring network of workstations interconnected on a single simplex ring is converted to duplex communications on the single ring by placing two transceivers in each workstation and adding a duplex conversion device between each workstation and its ring terminal box. One of the transceivers receives and retransmits signals in a clockwise direction around the ring; the other transceiver receives and retransmits signals in a counter-clockwise direction around the ring. The clockwise and counter-clockwise signals are superimposed on the ring but are isolated at the workstations by the duplex conversion device.