Abstract: A transmission path interface apparatus compatible with a CSMA mode capable of responding to a fault occurring in a transmission path flexibly and at a high speed, including a transmission unit for holding serial transmission information and transmitting a frame modulated by both of the transmission information and a preamble to a CSMA mode transmission path; a reception unit for taking out a loopback frame transmitted by an opposing node in accordance with that frame, restoring the transmission information contained in this, and holding the same; a collision decision unit for determining a correlation between transmission information held by the transmission unit and the reception unit and notifying a result of this to an information source of transmission information; and a collision decision acceleration unit for comparing an elapsed time from a timing when the information source gave the transmission information to the transmission unit to a timing when the transmission information contained in the loopba

Abstract: A communications management system service as an interface between an ADSL (Asynchronous Digital Subscriber Line) terminal and an ATM exchanger. The system includes a control section, an upstream cell processing section, and a down stream cell processing section. The control section receives user cell signals from a subscriber terminal and converts the user cell signals to ATM cells. The upstream cell processing section then converts the ATM cells into signals for transmission to a subscriber control system. The downstream cell processing section converts signals received from the subscriber control system to ADSL signals to be sent to the subscriber terminal. The ADSL signals may be E1 signals. To check for errors in the system, the controller sends a test cell through the system. When the test cell loops back to the controller, it is compared to the test cell as it was initially generated. A decision concerning system errors is then made based on this comparison.

Abstract: A method for evaluating an end-user's subjective assessment of streaming media quality includes obtaining reference data characterizing the media stream, and obtaining altered data characterizing the media stream after the media stream has traversed a channel that includes a network. An objective measure of the QOS of the media stream is then determined by comparing the reference data and the altered data.

Abstract: Error detection in a fiber-channel arbitrated loop (FC-AL) is facilitated by incorporating certain error detection circuitry in FC-AL adapted electronic devices. Transmission circuitry is provided to transmit diagnostic frames during periods when the electronic device has no pending output transactions. Receiver circuitry is provided to perform CRC checking of each received frame.

Abstract: A packet data service node is formed to establish an “always on” connection with a mobile terminal by way of a packet control function card or device with the ability to determine when a mobile terminal no longer requires a previously established point-to-point protocol communication link. More specifically, the PDSN formed according to one embodiment of the present invention, includes an inactivity timer and corresponding logic to prompt it to generate an LCP Echo Request to the mobile terminal after expiration of the inactivity timer. Each time data or control signals are received from the mobile terminal, the inactivity timer is reset. Upon expiration of the timer, the PDSN generates the LCP Echo Request.

Abstract: The present invention involves a transmission of a known signal over a line intended for a digital subscriber line (xDSL) service, measurement of a resulting waveform received through the line and processing of the received signal to derive a set of eigenvalues characterizing the transfer function of the line. In the preferred embodiment, a transmitter applies a known test signal waveform to the transmission line. The test signal corresponds to a desired one of several available xDSL services. At the receiving end of the line, the output signal from the line is sampled, to capture a digitized sample waveform for the received signal. A computer processes the captured waveform to determine eigenvalues characterizing the transfer function of the line with respect to the one service. If the eignevalues for the line bear predetermined relationships to threshold values, indicating acceptable line transfer function for the desired xDSL service, then the invention certifies the tested line for use on that service.

Abstract: A hybrid network (100) includes a plurality of network elements (102, 106, 110, 114) that are coupled together by communication links (116, 118, 120, 122, 124). The network elements operate on different communications protocols. A loop back test message traverses a path (140) across network elements to test the integrity and quality of the path. Each network element that receives the loop back message modifies the message in a predetermined manner. The originator of the message verifies that the message was modified in an appropriate manner and in an appropriate time frame to determine integrity and quality.

Abstract: A switch to switch protocol for network load balancing which negotiates among switches operable in accordance with the invention to assign a unique loop bit offset identifier value to each switch. Various other load balancing protocols associated with the switches then utilize the loop bit offset value as an identifier field when determining loops in the network of switches and costs associated with non-looped paths in the switches. A loop bit offset identifier requires less switch processing overhead than techniques which utilize an entire address value (i.e., MAC address value) for such protocols. Further, the loop bit offset identifier assigned by the present invention reduces the size of load balancing related packets. Specifically, cost computation related packets are reduced in size to the minimum 64 byte packet size through use of the loop bit offset identifier value of the present invention.

Abstract: A method triggers the transmission of a flow control packet between a receiving device and a sending device on the basis of space available to receive data in a buffer associated with the receiving device. The method increases throughput in a system that requires a flow control packet every predetermined number of clock cycles.

Abstract: Loopback interfaces are put into routers in a packet switched network. When an end to end Quality of Service (QoS) path is not performing adequately, the delay and jitter characteristics are measured for individual network subsystems. An audio signal is converted into a stream of audio packets and sent hop by hop to the different routers in the network having the loopback interface. QoS is determined by looping back the stream of audio packets from the different routers. If necessary, the network is reconfigured according to loopback delay in the individual network subsystems. Reconfiguration can comprise routing telephone calls through different paths in the network or adding additional equipment to increase capacity.

Abstract: A looping detection apparatus used in a frame-relay communications system and capable of detecting looping without fail through confirmation of link completeness according to a two-way PVC status confirmation procedure. A status enquiry message transmitting unit transmits a status enquiry message with a first identification code carried at a predetermined position of a signal by means of which the status enquiry message is transmitted. On receiving the status enquiry message, a status response message returning unit creates a status response message based on the status enquiry message and sends the status response message back to a first node with a second identification code carried at the predetermined position.

Abstract: A method and system for determining the high speed data service capability of a subscriber line includes sending an embedded test signal to a subscriber line. A reflected signal received in response to the test signal is analyzed for determining transmission characteristics of the subscriber line. Based on the reflected signal, a determination about the high speed data service capabilities of the subscriber line is made and stored for future reference.

Abstract: A technique manages packets in a data communications device having a memory using a real-time feedback signal. The technique involves transmitting an initial set of packets from the data communications device. The technique further involves monitoring transmission of the initial set of the packets from the data communications device, and providing the real-time feedback signal indicating transmission information regarding the initial set of packets. Additionally, the technique involves manipulating a new set of packets within the memory of the data communications device based on the real-time feedback signal, and transmitting the new set of packets from the data communications device based on how the new set of packets was manipulated within the memory of the data communications device. The use of the real-time feedback signal enables the data communications device to make on-the-fly adjustments to dynamically changing traffic patterns without the need for human intervention.

Abstract: A DMT (Discrete Multi-Tone) test method is provided. The test method is employed by two test devices to estimate the theoretical and practical data rates of a cable under test for a pair of target ADSL (Asymmetric Digital Subscriber Line) DMT modems. The present DMT test can also be used to analyze the cause of, or to predict a problem, whereby a pair of ADSL DMT modems could fail to synchronize. The method includes (a) synchronizing two devices at lower frequencies; (b) measuring the frequency characteristics of the cable with test signals; (c) measuring the cable noise and interference for every sub-channel of the ADSL bandwidth; (d) determining the theoretical and practical data rates for every sub-channel, based on the measured frequency characteristics and noise characteristics, as well as modem parameters selected by the user; (e) estimating the theoretical and practical data rates for the ADSL bandwidth based on the ADSL DMT standard selected by the user.

Abstract: A method and system for transmitting acknowledgments from an acknowledgment queue in a receiving system to a receiving system in response to receipt of a data packet from the receiving system is disclosed. An acknowledgment compressor co-located with an acknowledgment queue of the receiving system compresses a plurality of acknowledgments within the acknowledgment queue into a single acknowledgment packet. The single acknowledgment packet is transmitted from the receiving system to the sending system over a packet data network wherein it is intercepted at some point by an acknowledgment decompressor prior to receipt by the sending system. The acknowledgment decompressor regenerates the plurality of acknowledgments from the single acknowledgment packet and transmits the decompressed plurality of acknowledgments to the sending system.

Abstract: A method of measuring the Round Trip Time (RTT) if a Virtual Circuit (VC) utilizing the Traffic Management mechanism of ATM. The RTT is measured in real time individually for each new opened VC and/or for existing VC routes in the network. In addition, the RTT measurement method of the present invention can be used to determine the CRM parameter for a VC on an end to end basis, e.g., user to user or LEC to LEC, so as to achieve better performance of the network. The invention comprises a first embodiment that utilizes the SN field of a RM cell in measuring the RTT and a second embodiment that does not utilize the SN field in measuring the RTT. In addition, an application of the method is presented in determining the CRM parameter within the TM descriptor.

Abstract: A switching system in an ATM switching system accommodating an ABR is constructed of an individual units connected to a transmitting terminal or a receiving terminal to implement an efficient bandwidth authorization, and a plurality of intra-system relay devices having transmission allowed rate calculating units. In this switching system, there are separated a transfer of a management cell between the transmitting terminal or the receiving terminal and the individual unit and a transfer of the management cell between the plurality of intra-system relay devices.

Abstract: A method and apparatus for automated sectionalization of a DS1/DS3 data path based upon information received at a single location along the path. A test and monitor device is located at a point of demarcation between an LEC and an IEC. A Remote Module is located at a point of demarcation between the LEC and CPE. The test and monitor device is fully ANSI compatible. The information that is received is processed in a three step process in order to generate a “Sectionalizer Report”. In preparing the Sectionalizer Report, the information output from a filter is used to determine where particular Events originated.

Abstract: A method to increase the capacity efficiency of span-restorable mesh networking on sparse facility graphs. The new approach views the network as a “meta-mesh of chain sub-networks”. This makes the prospect of WDM mesh networking more economically viable than with previous mesh-based design where the average nodal degree is low. The meta-mesh graph is a homeomorphism of the complete network in which edges are either direct spans or chains of degree-2 nodes. The main advantage is that loop-back type spare capacity is provided only for the working demands that originate or terminate in a chain, not for the entire flow that crosses chains. The latter “express” flows are entirely mesh-protected within the meta-mesh graph which is of higher average degree and hence efficiency for mesh restoration, than the network as a whole. Nodal equipment savings also arise from the grooming of express lightpaths onto the logical chain-bypass span.

Abstract: A communication device which efficiently transports packets through optimal routes. When there are two or more routes to reach a certain destination, a test packet generator generates a test packet for each route, one of them being designated as the reference test packet. A transmission time acquisition unit records the transmission time of each test packet, relative to that of the reference test packet. When a test packet is received, a reception time acquisition unit measures its reception time relative to the reception time of the reference test packet. Calculating the difference between the transmission and reception times and evaluating such difference values for all routes, a transport time evaluation unit ranks the routes in terms of their packet transport times. A packet transmitter selects an appropriate route from the ranked list of possible routes, and sends out packets to the selected route.

Abstract: A test system which can verify the internal connectivity in an ATM switching system by using loopback OAM cells, without establishing any dedicated channels or using special cells newly defined for test purposes. The connectivity test system produces a loopback OAM cell containing a local subsystem identifier in a predetermined field thereof to designate a specific local subsystem in the ATM switching system as the intended loopback point. This loopback OAM cell is transmitted to the ATM switching system by a transmission unit. A response unit, disposed in each local subsystem in the ATM switching system, receives the loopback OAM cell from the transmission unit through a certain physical link, and it checks the predetermined field of the received loopback OAM cell. If the identifier found in the field agrees with the local subsystem's own identifier, the response unit sends back the received loopback OAM cell through the same link so that it will be returned to the originator via the same route.

Abstract: A repeater for HDSL transmission is presented. The repeater replaces the regenerator commonly used in HDSL by utilizing the activation/deactivation process in the HDSL specification. The repeater is adjusted to detect an activation/deactivation sequence, whereby a flip-flop in the repeater is alternated. A first state of the flip-flop allows transmission passing through the repeater to the terminating point, e.g. a network terminal, and a second state loops transmission back to the originating point, e.g. a line terminal. The looping may then be utilized for maintenance and error detection and recovery. By use of one of the free bit in the overhead channel in the HDSL transmission as an origin bit, wherein “1” is set in the upstream direction, and “0” is set in the downstream direction, it is possible to detect at the line terminal whether there is a loop in the repeater.

Abstract: A circuit and method for testing a transceiver. The circuit includes a bit pattern generator connected to the transceiver such that the bit pattern generator can communicate a serial data stream to a receiver portion of the transceiver. The circuit also includes a bit pattern checker connected to the transceiver such that a transmitter portion of the transceiver can communicate a serial data stream to the bit pattern checker. The transceiver is configured such that the receiver portion of the transceiver is communicatingly looped back to the transmitter portion of the transceiver such that a data stream can be communicated from the receiver portion of the transceiver to the transmitter portion of the transceiver. Desirably, a loopback circuit in connected to the transceiver and includes fixed bit pattern means for communicating at least one fixed bit pattern to the transmitter portion of the transceiver.

Abstract: A method for transmitting data between radio stations in a radio communication system includes superimposing first signaling information items with second information items at a transmitting end to form an aggregate signal. The aggregate signal is transmitted in a frequency channel, for distinguishing the first signaling information items and the second information items with the aid of individual fine structures. A received signal is evaluated at a receiving end. Initially an influence of the first signaling information items on the second information items is reduced by a compensation calculation carried out with reference to the received signal. Subsequently, the second information items are detected in the received signal already subjected to the compensation calculation. The method can be used in particular with a TD/CDMA transmission process. A receiver and a mobile station are also provided.

Abstract: A switching apparatus that is used for high-speed large-capacity routing and a communication apparatus and communication system that are used for an efficient recursive multicast. A matrix switch performs self-routing on a packet on the basis of a tag including output route information set in the packet. Selectors are located so as to correspond to N output ports P#1 through P#N of the matrix switch and perform N-to-one selection control. Setting registers hold selection information used by the selectors to select a signal.

Abstract: In a state monitoring method in a subscriber line test in a communication system in which a subscriber telephone and a subscriber terminal are independently connected to a telephone exchange and an ADSL (Asymmetric Digital Subscriber Line) apparatus through a subscriber line, the telephone exchange to which a first control terminal is connected is connected, through an interface, to the ADSL apparatus to which a second control terminal is connected. A line blocked state due to a line test instruction is notified from one of the first and second control terminals to the other of the first and second control terminals through the interface. Upon receiving the notification of the line block state due to the line test instruction, the other of the first and second control terminals determines that the line blocked state is not caused by a fault. A state monitoring apparatus is also disclosed.

Abstract: A random early detection (RED) methodology controls and avoids congestion in a packet network by anticipating congestion and periodically signaling congestion by marking or discarding packets. Sources respond to marked packets by slowing their transmission rates. Enhancements to the basic RED methodology improve performance and reduce buffer requirements in network switches. RED decisions are made as packets leave queues in switches, and RED marks can be accelerated from one packet to another. System response is linearized, and the RED process specifies a marking rate or period rather than a marking probability. A control algorithm permits a single queue operating point. Specific measures are provided for selecting which connection should be marked, and per-connection weight parameters allows customized treatment of connections.

Abstract: A method and system for transmitting a loopback cell within an ATM connection. The method comprises the steps of detecting in an input adapter whether or not an incoming ATM cell includes a loopback condition indicator. If so, specific routing labels are appended to the incoming ATM cell indicating that the incoming cell is a loopback cell to be looped back on the connection such that the switch engine of the switching node transfers the loopback cell to the same port of the input adapter utilizing the appended routing labels.

Abstract: An ATM transmission system without having a dedicated line for transmitting maintenance information between subsystems constituting the ATM transmission system. The ATM transmission system introduces the idea of a multiframe for transmitting ATM cells, and transmits the maintenance information by inserting it into an overhead portion of the multiframe. This enables the number of lines interconnecting the subsystems to be reduced. The ATM transmission system includes in its interface circuit a set of parallel processors of the same configuration. The number of the parallel processors equals the least common multiple of ratios between the minimum interface rate and one or more other interface rates of other ATM transmission subsystems interconnected to the ATM transmission system. This enables the subsystems with different interface rates to become the interconnected ATM transmission system.

Abstract: A method of path restoration in an ATM network which attempts to minimize the loss of cells in the event a node or a link fails. The method is suitable for failures in point to point Switched Virtual Circuits (SVCs) in ATM networks and makes use of the bi-directional properties of point to point SVC calls. The method permits the construction of an ATM network which includes call path redundancy whereby if a node or link fails, another path meeting the requirements of the call (if one exists) will be used on an automatic basis. The alternative or redundant path is placed into service in such a way that the flow of data is substantially constant. The switching of the path occurs with almost no data loss and without the overhead time associated with Q.SAAL based detection and signaling.

Abstract: A communication route monitoring system monitors a communication route in an ATM network with OAM loopback cells. The communication route monitoring system has a first OAM loopback cell delivering unit disposed in one of the communication devices which performs a network management function, a first returning and relaying unit disposed in each of the communication devices, and a communication route recognizing unit disposed in the communication device which performs the network management function. The first OAM loopback cell delivering unit delivers a first OAM loopback cell for confirming a communication route to a route terminal point. The first returning and relaying means returns the first OAM loopback cell upon reception of the first OAM loopback cell, together with its own location identification added thereto, to a source, and relays the received first OAM loopback cell to a next one of the communication devices.

Abstract: A restoration procedure for use in bidirectional multiplex section-switched ring transmission systems re-establishes a connection path by using a loopback connection at nodes bordering the failure and by then establishing a jumpered connection path, for each active tributary affected by the failure. The jumpered connection path at affected node eliminates any unnecessary loop formed in the re-established connection path caused by the loopback connection at the border nodes. There is stored in memory at each node (1) the provisioned connection path, (2) the jumpered path, and (3) a jumper flag is set indicating that a jumper connection exists. When the failure is cleared the (1) jumpered path is removed and its record erase from memory, (2) the provisioned connection path is restored, and (3) the jumper flag is reset. Advantageously, the this operation can be programmed into existing node controllers and is compatible with existing restoration procedures.

Abstract: A unique byte is used to bookend commands and data for the purpose of allowing inband signalling and command communication between the IWF and the BSC portions of a mobile communication system having DS0 maximum data rate transfer capability per data channel. The receipt of two consecutive ones of the unique bytes indicates that the next 2 bytes will be a command. The receipt of 3 consecutive ones of the unique bytes indicates the next byte will be data. This inband signalling and data transfer allows the IWF functionality to be remote from the main switch used by a given BSC. The CDMA system uses the inband signals to pass a plurality of data packets in parallel on DS0 capacity channel links through the MTX in a half-duplex burst whenever a data buffer within the IWF or a connected high data transfer rate mobile station is filled to a given level. This burst process may operate on a time multiplex basis with low speed data transfers using the same DS0 links to communicate with the IWF.

Abstract: In some call-switching systems, transmitted speech samples may be sent back (back-looping) to the sender from a telephone switching center if the switching center is unable to send the speech samples forward. When supplementary information is sent with the speech sample, back-looping may cause a problem if the sending device interprets the signal as originating from another device. To avoid this problem, transmitted samples are subjected to a check value calucation such as a checksum or a cyclic redundancy check. The check value is stored in memory and any received samples are subjected to a check value calculation and compared to the stored samples. If the comparison yields a match, then the device will know that the received samples originated from itself and can be properly handled.

Abstract: A method and apparatus for replacing lost PSTN data in a packet network and for generating variable power white noise are disclosed. In one embodiment, the method for replacing data includes the steps of receiving data packets, detecting lost data packets, and producing in response a lost data output indicating when replacement data needs to be provided. The method preferably generates the replacement data by re-using data stored in an extended playback buffer (with the re-used replacement data starting with the oldest output data byte stored in the extended playback buffer), and placing the re-used replacement data on an external network. Another aspect of the invention is a variable power white noise generator for providing replacement data. The variable power white noise generator may use, for example, a multi-bit register that stores a magnitude, and a pseudo-random sign bit generator to change the positive and negative sense of the magnitude.

Abstract: A portable ISDN test set is configured to be interfaced with any location of an ISDN link, and is operative to test the link, irrespective of the hardware configuration of the circuit, (e.g., two-wire vs. four-wire). The ISDN test set contains a digital communications controller and associated digital signalling interface circuits, including both ‘U’ interface and ‘S/T’ interfaces. The ISDN test set and a remote device, such as another test set, exchange digital communication messages over an auxiliary ISDN channel, such as an embedded operations channel or a Q channel, that are effective to cause the device to provide a loopback path over at least one ISDN bearer channel to the test set and test a prescribed operational characteristic of the link.

Abstract: A system and method for connecting a voice band link box to a telephone switch to facilitate trunk-related testing. The system includes a remotable trunk transmission unit being interconnected to the telephone switch and interfacing with the testing device, a voice band link box having an input interface being interconnected to the remotable trunk transmission unit and an output interface being interconnected to a digital trunk of the telephone switch, and an output device being interconnected to the telephone switch. The testing device interfaces with the remotable trunk transmission unit and places a call by transmitting an analog signal via the remotable trunk transmission unit directed to the output device. The voice band link box receives the analog signal at its input interface, converts the analog signal to a digital signal and routes the digital signal from the output interface over the digital trunk of the telephone switch. The call is received at the output device.

Abstract: In a cell exchange, cell diagnosis of continuity with respect to an individual part operating in a band width for a speed faster than a cell feeding speed is enabled by using cell test equipment with a low cell feeding speed. The method of cell diagnosis of continuity for this purpose comprises a step of setting a plurality of paths between a diagnosed unit to which the cell diagnosis of continuity is applied and the cell test equipment; a step of almost substantially concentrating cells sent from the cell test equipment through a plurality of paths at the diagnosed unit; and a step of returning cells concentrated at the diagnosed unit to the cell test equipment via one of a plurality of paths.

Abstract: A method of determining a restoration route as in a fully or partially meshed communications network of nodes, comprising setting, at a slave end node for an existing route, a timeout for receiving a number of forward route-finder signatures from which it will select the signature representing the potential restoration route having the shortest length and return a route confirmation signature; switching, to act as master end node for the existing route and send reverse route-finder signatures to its neighbouring nodes; switching, upon receipt of a reverse route-finder signature at a master end node for an existing route, to act as slave end node, and send a corresponding return signature. Where a slave end node receives a backtrack signature indicating that the potential restoration route no longer has sufficient capacity, the node will switch to act as master end node.

Abstract: The present invention provides a network in which the installation of working lines may be enabled based on the required traffic and the high speed switching of the transmission lines may be realized, as well as a transmission equipment used for that network and a method of control thereof.The transmission equipment comprises an APS byte transmitter/receiver for exchanging information on failures with adjacent transmission equipment through a protection line, a monitor for monitoring anomalies on a plurality of the working lines, a Network Table for storing data indicating network structure, a processing unit for determining working lines to be switched based on the data stored in the Network Table and for processing APS bytes.APS bytes are allocated with the working line number, its priority, and the source node number of switching signal.

Abstract: A preferred embodiment of the present invention provides a cell site base station configuration for a wireless communications system that makes use of a sectorized base station co-located with an omnidirectional base station. The sectorized base station has a sectorized antenna system and the omnidirectional base station has an omnidirectional antenna. The configuration may also include a controller that monitors the base station for communications links subject to adverse conditions and reassigns any such links to the omnidirectional base station. The adverse conditions monitored for may include multiple fade, equipment failure and a lack of available channels. The controller may also monitor the omnidirectional base station for links that can be moved to the sectorized base station and reassign any such links to the sectorized base station. The configuration may also include a network that interconnects the sectorized base station, the omnidirectional base station and the controller.

Abstract: High-speed digital transmission can be achieved with existing phone lines and HDSL chipsets. Two original ISDN signals [4,5] at a rate of 160 kbps are multiplexed by a MICS card [6] of a signal provider [1]. The resulting digital signal is transported over a twisted cable pair [2] which has an approximate maximum length of 16 kft. At a receiving end, the signal is demultiplexed and regenerated by a subscriber's MICS card [7]. The subscriber's MICS card is line-powered via the cable [2] to avoid dependence upon local power. The regenerated signals are transmitted over two ISDN cables to remote premises which can be as far as 18 kft away.

Abstract: A computer system employs a hierarchical ring structure for communication. Computer system elements are configured into modules with ring interface hardware, and the modules are coupled to one or more rings. Bridge modules may be included for transmitting between rings in the hierarchy. The rings are time division multiplexed, and each time slot on a ring carries a frame. According to an address carried within the frame, bridge modules determine whether or not to transmit a frame circulating on a source ring onto a target ring. If the address of the frame indicates a module upon the source ring, the bridge module retransmits the frame on the source ring. Otherwise, the bridge module transmits the frame on the target ring. The bridge module operates in this fashion at any level of the hierarchy. The owner of a time slot on a ring is permitted to release the time slot for use by other modules. To reclaim a time slot, the owner marks the time slot owned.

Abstract: Specific ABR control capability for implementing an ABR service in an ATM switching system. A subscriber line processing device has a capability for calculating a turnaround delay time of a cell, based on a period during which the cell loops back at a terminal and returns. A switch or demultiplexer has a capability for detecting congestion. A rate calculator calculates a transmission rate corresponding to an output channel, and writes the calculated rate to the cell. A rate changer suitably changes the transmission rate according to the degree of occurrence of congestion. Additionally, the rate changer counts the number of communicating connections. At this time, the number of communicating connections which should exist in a certain predetermined period is estimated based on the counted number of communicating connections, which is counted in a period shorter than the predetermined period according to a predetermined method.

Abstract: The present invention generally relates to a network and method capable confirming proper communications of high data rate optical signals between communications network devices. In particular, the present invention teaches a method of creating a "Line Trace" byte to be placed in the Line Overhead portion of the Transport Overhead of a SONET STS-1 frame optical data signal. Current Line Overhead does not incorporate any Trace functionality. With the increasing use of optical cross-connect switches within a communications network, it is essential for a network service provider to have the flexibility to move Line Terminating Equipment around via the optical switches. Thus, the present invention offers a straightforward, efficient way to achieve this necessary flexibility.

Abstract: A noncooperative feedback system is provided for a compensation system associated with, for example, a transmitter or codec, for enabling the compensation system to improve the accuracy of digital signals transmitted to a, digital network. The noncooperative feedback system is particularly suited for providing feedback to a compensation system for correcting distortion resulting from rob bit signaling (RBS), digital loss, or other types of digital signal degradation. The noncooperative feedback system includes a compensation selector in a transmitter (e.g., digital modem, analog modem, codec, etc.) that combines different compensations with frames of digital data by way of an addition mechanism to produce modified digital data frames. The transmitter is configured to transmit the modified digital data frames into the digital network. A receiver (e.g., digital modem, analog modem, etc.

Abstract: An automated closed-looped test system and method for testing network devices such as CPE and system network managers is arranged as a modular, comprehensive test system which seamlessly integrates physical layer testing with higher layer services protocol testing. A set of tests are generated based on the device or manager being tested. A selection menu provided via a GUI such as a Web browser allows a user to select the desired test option to be run. Test results are output in real time via the GUI, and can be logged in a form suitable for documentation.

Abstract: Telecommunications networks require a variety of tests to monitor their proper operations. Performance monitoring (and fault detection) of the physical layer of a transmission system is one of them and is usually accomplished by using a bit error rate test (BERT). The BERT of the invention uses modified ATM idle cells to conduct one-way, bidirectional and loopback BERT. ATM idle cells are loaded with BERT data at the transmit end and recovered at the receive end. The BERT data are processed according to the different data rates of the ATM transmission system. Performance parameters are derived from the received BERT data. The disclosure describes a method as well as a system for performing such a test.

Abstract: An error indicator indicates plural errors with a light emitter. A MPU checks each section in a data modulator-demodulator, and flashes an error LED at a standard cycle when any error occurs. When an user turns ON an error check key in flashing at the standard cycle, the MPU varies a flashing cycle of the error LED in accordance with the detected error. Moreover, a light emitter in a data modulator-demodulator indicates whether a remote loop back test is executed by a trigger from a self-station or from other station. The MPU lights a test LED and shifts the data modulator-demodulator to an execution state when any switch is turned ON. When any of test switches except for local digital/analog loop back test is turned ON, the MPU transmits a test command corresponding to the test switch which is turned ON to other data modulator-demodulator. The other data modulator-demodulator flashes the test LED and is shifted to the execution state corresponding to the received command.

Abstract: In a digital communication device adapted to be coupled to a digital network and having an analog port adapted for interconnecting an analog device to the digital communication device, a device for generating and detecting tones, includes: a processor programmed to selectively generate one of a first set of digital tones in a generation mode and to detect one of a second set of digital tones in a detection mode; and a conversion circuit, operably coupled to the processor, adapted to convert the one of the first set of digital tones generated by the processor in the generation mode to an analog tone and transmit the analog tone to the analog device; the conversion circuit further being adapted to convert an analog tone received from the analog device to the one of the second set of digital tones and transmit the digital tone to the processor when the processor is in the detection mode.