Abstract: The present invention provides a test access path (TAP) concentration function. The apparatus supports subscriber loop testing for special access configurations (e.g., fiber-to-the-curb (FTTC)), where network units are physically clustered together into two or more non-collocated clusters. The apparatus supports test access to twisted wire pair subscriber loops, the lengths of which vary over a wide range. In one embodiment, the apparatus is a TAP expander that connects the TAP of an integrated digital terminal of a local digital switch with a derived TAP corresponding to one of the ONU clusters. The present invention allows an integrated digital terminal with as few as one test access path to be configured in a network having two or more non-collocated network unit clusters (e.g., ONU clusters), thereby supporting loop testing for all of the subscriber loops served by the integrated digital terminal without unnecessarily limiting the number of those subscriber loops.

Abstract: Line coding mismatches on a transmission channel in a telecommunications network will manifest a constant error signature having a certain number of errored seconds, severely errored seconds, unavailable time and lost sync. errors upon the application of a test pattern comprising a sequence of a first, second and third octet, each repeated a prescribed number of times. The first and second octets remain constant regardless of the nature of the transmission channel, while the nature of the third octet varies according to the transmission rate of the DS0 under test and associated DS1 under test. The test pattern will reveal a line coding mismatch. In a B8ZS environment (64 Kbps clear channel capability), the pattern may be run on any DS0 channel within the DS1. In an AMI-with-ZCS environment (56 Kbps or 64 Kbps restricted), the pattern must run on either channel 1 or 24.

Abstract: Dynamically adjustable hybrid two-way data networks are described which provide a high degree of connectivity. In one embodiment, a two-way CaTV system uses the CaTV plant most of the time, but also uses the public switched telephone network (PSTN) as a back-up whenever upstream or downstream connectivity between a cable modem and the CaTV head end (H/E) is severed. Management elements are provided for a fully operational two-way CaTV network which uses PSTN connections as an “on-the-fly” back-up mechanism for rare occasions when the CaTV plant looses its upstream and/or downstream connectivity. On the end-user side, a hybrid two-way CaTV/PSTN network provides added intelligence in either the cable-modem box, which may be enhanced with a regular voice-grade modem, or in the PC attached to the cable modem, to automatically handle both communications media.

Abstract: The present invention relates to a subscriber control module having a test apparatus suitable for testing internal routes in an Asynchronous Transfer Mode ATM exchange system for improved reliability and effective maintenance thereof. A subscriber control module having testing functions makes it possible that internal whole routes in the exchange system under the control by maintenance control module inside the system can be tested through the use of subscriber switching network and connection switching network. Further, a test apparatus of the present invention placed inside the exchange system can test ATM subscribers with individually different rates, configured in such a way to be identical with boards used in the exchange system so that the test apparatus can be installed inside the exchange system.

Abstract: A method and apparatus for protection against loss of data in a fractional T1/E1 communications environment utilizes a message signaling arrangement between data service units and/or channel service units (DSU/CSU) to detect interruption in data transference occurring within a common carrier network due, for example, to an out-of-service condition. A “heartbeat” signal in a proprietary message format is generated and sent on a periodic basis to one or more destination DSUs/CSUs through the common carrier network over a separate T1/E1 maintenance channel. A selectable duration watchdog timer at each DSU/CSU is reset every time a heartbeat signal message is received from a remote unit. If the heartbeat signal is not received within the specified amount of time, the watchdog timer expires triggering the DSU/CSU to enter a dial back-up mode wherein an alternate communications link is established.

Abstract: An apparatus for monitoring selected one of multiple channels comprises a counting unit for increasing a count value when an up mode is selected and for decreasing the count value when a down mode is selected, wherein the count value corresponds to a channel number of the multiple channels; a mode selecting unit for selecting one of the up and the down modes; a unit for inputting a channel number; a unit for generating a count value corresponding to the channel number from the inputting unit and a write-enable signal; a source selecting unit for selecting one of the count values from the counting unit and from the generating unit; a signal generating unit for generating a channel selecting signal corresponding to the count value; a converting unit for extracting data from a channel depicted by the channel selecting signal and converting transmission rate of the data; and an analyzing unit for monitoring the data from the converting unit to check whether or not the data is transferred properly.

Abstract: A portable ISDN test set contains test circuitry that is controllably operative to automatically test the ISDN communication capability of an ISDN circuit. In response to a user operating a prescribed input/output element of a user interface of the test set, the test set's supervisory control processor executes a routine that places an ISDN call over a first bearer channel of the ISDN circuit, the first bearer channel having a first directory number, through a public switched telephone network to a second directory number associated with a second bearer channel of the ISDN circuit. The ISDN call is thus routed by the public switched telephone network back to the ISDN test set. When the ISDN call is received by the test set, it is automatically looped to the public switched telephone network, so that the call is rerouted to the first directory number associated with the first bearer channel to the ISDN test set.

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: A method and apparatus for monitoring signals communicated over a signal path from a source to a destination with the signals containing a set of data representing a data signal type comprises a first device for accessing a first portion of the data set from the received signal and generating a first indication signal relating to a status of the received signal; a second device for accessing a second portion of the data set from the received signal and generating a second indication signal relating to a further status of the received signal; and, a device for generating a composite signal representing a combination of the first and second indication signals for indicating a specific status of the received signal. The types of signals include normal VC-n signals, unequipped VC-n signals and supervisory-unequipped VC-n signals communicated in an SDH/SONET network, the composite signal capable of uniquely identifying receipt of unequipped VC-n signals over a signal path in the network.

Abstract: A conservative algorithm for pruning data paths during logic circuit timing verification is disclosed. It uses the correlation between delays on data paths and clock paths in order to prune non-critical data paths during the traversal of the network. Subnetworks are identified in the larger network. Pruning data consisting of the minimum possible delay across all possible paths through the subnetwork, the deskewing clocks, the clock arrival times, and hold times at the synchronizers in the subnetwork are identified the first time each subnetwork is analyzed. In later analysis, the pruning data stored for each subnetwork is used to determine whether a data path can be pruned. A path can be pruned if it is shown to be race-free based on the pruning data. In this way, non-critical paths need only be traced once during timing verification.

Abstract: A resource model for modeling the resources of a telecommunication network that uses a number of different switching technologies. The resource model comprises three layers, a network layer, a node layer and a component layer, each layer comprising resource objects. The resource objects of the network layer are encapsulated to applications which use the network. The resource objects of the node layer are encapsulated to the resource objects of the network layer and the resource objects at the component layer are encapsulated to the resource objects of the node layer. The resource model comprises connection handling function for setting up connections in the telecommunication network. The functions are divided into function components.

Abstract: A user-configurable frame relay network system is provided. In accordance with one aspect of the invention, the system is designed around a service provided frame relay network. More specifically, a plurality of frame relay user equipment are configured to intercommunication via one or more primary communication links that pass through a service provided frame relay network. At least one frame relay access unit is interposed between the service provided frame relay network and each frame relay user equipment. In this way, communications between the various frame relay user equipment pass through the frame relay access units. At least one secondary communication link extends from a first access unit of the plurality of access units to a second access unit of the plurality of access units, the at least one communication link being outside the service provided frame relay network.

Abstract: A maintenance and supervising system and method for a multiplex communication system having mutually connected multiple pieces of multiplex communication equipment. A call controller executes call control by common channel signaling. A multiplexer multiplexes multiple communication data, and a fixed connection allocation device allocates multiplexed data within a multiplex circuit fixedly. A dynamic connection allocation device allocates multiplexed data within the multiplex circuit dynamically, and a piece of connection form switching equipment is provided. A piece of terminal equipment for maintenance and supervising is connected to one of the pieces of multiplex communication equipment.

Abstract: A method of monitoring the integrity of the path and flow of digital PCM data from a source end to a receiving end which includes generating a pseudo-random sequence of bits at the source end, transmitting the pseudo-random sequence of bits together with the PCM data through a transmission path to a receiving end, and applying the pseudo-random sequence of bits to a pseudo-random bit sequence checker at the receiving end.

Abstract: A wireless local area network allows roaming of a mobile unit to allow it to serially associate with a number of access points of the network fixed backbone. This roaming is supported by an improved measurement of communications link quality, which includes calculating a mean error free length of a test pattern broadcast by each access point and received by a mobile unit. The test pattern is a digital data message. Thus an accurate measurement of link quality is provided which allows a mobile unit to determine whether it should change its association to another access point having improved communications link quality. Further, a load balancing process is provided to balance the communications load amongst a variety of access points, by allowing mobile units also to switch their association with access points in accordance with a current total data rate at any given access point and also considering the number of currently high data rate mobile units associated with a particular access point at any one time.

Abstract: A portable ISDN test set contains test circuitry that is controllably operative to automatically test the ISDN communication capability of an ISDN circuit. In response to a user operating a prescribed input/output element of a user interface of the test set, the test set's supervisory control processor executes a routine that places an ISDN call over a first bearer channel of the ISDN circuit, the first bearer channel having a first directory number, through a public switched telephone network to a second directory number associated with a second bearer channel of the ISDN circuit. The ISDN call is thus routed by the public switched telephone network back to the ISDN test set. When the ISDN call is received by the test set, it is automatically looped to the public switched telephone network, so that the call is rerouted to the first directory number associated with the first bearer channel to the ISDN test set.

Abstract: An ATM (asynchronous transfer mode) switching system is capable of performing a charging process, while suppressing a data communication amount used to acquire data required for a charging process. The ATM switching system is arranged by comprising: a charging data processing unit for counting a quantity of transmitted ATM cells with respect to each of transmission destinations, and for notifying the count value as charging data; a charging information processing unit for requesting the charging data processing unit to notify the charging data, and for notifying charging information produced based on the charging data; and a control unit for requesting the charging information processing unit to notify the charging information.

Abstract: In a telecommunications system, the amount of time a subscriber device is effectively out of service as a result of some fault or failure in telecommunications equipment is monitored. Subscriber devices are connected by corresponding subscriber communication paths to receive information from or transmit information to a telecommunications center such as a local telephone exchange. One or more data records is maintained in computer memory for each subscriber path connected to the communications center. Each data record is updated using recently determined data relating to the operational status of each subscriber path. The computer then determines from the updated record in accordance with one or more subscriber line blocking criteria a subscriber path blocking parameter. The subscriber path blocking parameter may represent for example an average amount of time each subscriber path satisfies the one or more subscriber line blocking criteria.

Abstract: An apparatus for and method of checking the validity of one or more directory numbers in a device for interfacing communications equipment to a digital telephone line, wherein the device is capable of accessing at least two channels on the digital telephone line, each channel having a directory number associated therewith, including: instructing the device to establish a plurality of protocol layers; initiating a call from the device over a first channel of the digital telephone line to the device over a second channel of the digital telephone line only if the plurality of protocol layers are established; and determining if the call is received by the device over the second channel to check the validity of the directory number associated with the second channel.

Abstract: A device for testing telecommunication terminals for telecommunication systems, in particular mobile radio systems, of the multiple access type, using a particular multiplex structure, transmits test information between the test device and a plurality of terminals under test by multiplexing in accordance with this multiplex structure.

Abstract: A system and method are provided for providing non-disruptive diagnostics between a first device and a second device in communication through a virtual circuit of a frame relay network. In accordance with one aspect of the invention, the method defines a diagnostic channel by assigning it a unique channel address, transmits a test command from the first device to the second device across the unique channel address, monitors the unique channel address for a response to the test command, and then evaluates the response to determine whether it reflects a fault in the virtual circuit. In accordance with one embodiment, the test command could be a pattern message, a connectivity request, a start send pattern command, a start loopback command, a start monitor pattern command, and a start send pattern command.

Abstract: A multiplex transmission apparatus, having a communication control circuit for carrying out transmit-receive control of a frame of data transmitted through a bus, and an output port for outputting data in frame received by the communication control circuit. The multiplex transmission apparatus is operated by a power supply voltage supplied from a power supply circuit to perform data communication with another multiplex transmission apparatus via a bus. First and second low voltage detection circuits, when detecting preset voltage values V.sub.L and V.sub.R of a power supply voltage, reset the communication control circuit and the output port. This multiplex transmission apparatus keeps the output of the output port in a normal condition despite relatively small variations in the power supply voltage (i,e., where V.sub.L .gtoreq.power supply voltage>V.sub.R).

Abstract: An enhanced ISDN-DP transmission device of the present invention allows for testing of ISDN-protocol communication paths using an existing DDS-protocol test infrastructure. The ISDN-DP unit receives a DDS test command and determines whether the command was intended for the immediate receiving unit or a tandem unit. If the command is intended for the immediate ISDN-DP unit, the unit processes the command. If the command is intended for another ISDN device in the transmission path, the ISDN-DP converts the DDS-protocol command to an ISDN-protocol command and transmits the converted ISDN command to an adjacent tandem ISDN device in the communication path in an upstream or downstream direction. After the test path is enabled, loopback testing is available on all available ISDN bandwidth, including the B1, B2 and D+ channels, from a DDS-protocol test set.

Abstract: A method and apparatus for monitoring the status of a speech connection between central office lines in a private exchange system may be constructed with a controlling unit for controlling a connection between a network and a corresponding central office line to perform a speech connection between first and second central office lines; a line interface unit for interfacing the first and second central office lines under the control of the controlling unit; a network unit for connecting the first and second central office lines to each other under the connection control of the controlling unit; and a speech monitoring the status of unit for monitoring the speech connection during the connection of the first and second central office lines, by directly detecting the presence or absence of a signal from the first and second central office lines inputted thereto through the network unit without interrupting the connection between the first and second central office lines and for outputting the speech connection s

Abstract: The present invention is directed to an apparatus and method that provides a universal call processing system to process all possible data types transmitted over an ISDN telephone line. A universal call processing system generally comprises an ISDN interface subsystem, a call control subsystem, a call processing subsystem, a controller state machine, and user interface devices.

Abstract: An SS7 Network Preventative Maintenance System for detecting potential SS7 and switched network troubles, automatically analyzing the troubles, providing alarm and corrective action to avoid major network events. Real time monitors on SS7 links at the STP provide information on exceeded link load, exceeded Message Signaling Unit (MSU) frequency and network management status/error conditions in a Stage 1 Process. The Stage 1 Process provides alarm information to a Stage 2 Process which controls all Stage 1 associated monitors for an STP pair. Stage 2 reacts to Stage 1 signals to generate alarm and corrective action information which is passed on to a Stage 3 Process. The Stage 3 Process controls all Stage 2 Processes in the operating company. Stage 3 reacts to Stage 2 output to detect potential or real accompanying network trouble and generates alarm and corrective action information and displays in response thereto. Stage 3 also alerts a Stage 4 process which is connected to all Stage 3 Processes in a region.

Abstract: The loopback test consists of a user-application interface that connects the network operator to substantially all of the ATM points in the network. In operation, the network operator selects two ATM points as the loopback and source endpoints for the loopback test. The virtual path identification (VPI), virtual channel identification (VCI) and payload type indicator (PTI) that will be in the address header of the test cell when it arrives at the loopback endpoint location and the identification of the loopback endpoint are transmitted to the loopback endpoint in a setup message via a link from the UAI. The VPI, VCI and PTI that constitute the address header of a test cell injected at the source endpoint and destined for the loopback endpoint, and the location identification of the source endpoint are provided to the source endpoint in a setup message via a separate link from the UAI.

Abstract: A digital communication network has a first end office which includes a first multiplexer unit and a second end office which includes a second multiplexer unit. The network performs transmission and reception of multiplexed signals between the first end office and the second end office. A monitor unit is provided within the first end office. Monitoring is performed of the accuracy of the signal received by the second end office from the first end office, signal accuracy information with regard to the received signal being included as subsignalling information in the input signal Sin which is input to the first end office from the second end office. The subsignalling information is extracted by the monitor unit from the input signal, so as to enable monitoring of the signal accuracy of the input signal. The result is a significant improvement in the improvement of transmission quality monitoring service provided in the digital communication network.

Abstract: A modular switch box which is responsive to a control signal, is diagnosable, and is not dependent upon the type of protocol being switched. There may be a plurality of switch boxes wherein each switch box includes a plurality of inputs and an output. There is a selector for selecting which input is connected to the output and a controller for controlling the selector. There is also a control means for controlling the switch boxes. The switch boxes are connected in a chain so that the input of one switch box is connected to the output of the next, etc., until the output of the last switch box is connected back to the controller. The controller sends a command message to the first switch box which then executes the command and forwards the message on to the next switch box, etc., until the command returns to the controller. In this manner, the controller knows that all switch boxes have received the command.

Abstract: Apparatus and method for testing lines. The apparatus is particularly useful for testing lines in a switched network, such as might be used to electronically route telephone and computer data lines to various offices in an office building. The apparatus includes an AC test source and a DC measurement device located at a near end switch. A DC transform circuit is located at a far end switch. According to the test method, an AC test signal is injected onto a line under test at the near end. At the far end, the received signal is converted to DC, which is sent to the near end. Line attenuation, and hence fault conditions, are detected by comparing the DC signal to the transmitted AC signal. Techniques to increase the signal to noise ratio of the DC signal are also disclosed.