Abstract: A signal classifier decomposes a subject signal into subbands. The signal classifier then analyzes the subbands for a presence of energy and uses detection logic to classify the energy as being representative of a frame of a signal using one of the following protocols: DTMF, MF-R1, ANS (V.25), LEC-DIS, V.21, or AA (i.e., telephone, facsimile, or modem). The detection logic is expandable to detect future protocols. The classifier may employ a preclassifier to select a reduced number of notch filters from among plural notch filters at frequencies which sinusoidal signals composing the energy in the subbands of the protocols may be found. A look-up table having predetermined ranges of data corresponding to the frequencies of the sinusoidal signals may be used to reduce calculation times. By splitting the subject signal into subbands and using efficient filters, the classifier uses an order of magnitude fewer processor instruction cycles than previous classifiers.

Abstract: Methods and apparatus for managing static and dynamic optical network configurations to enable mapping an actual optical network or validating an expected optical network are provided. In one embodiment a validation method includes the step of selecting an optical path having a plurality of nodes from a database defining an expected optical network. A list of detected pilot tones from each node associated with the selected optical path is generated. An expected list of pilot tones associated with each node of the selected optical path is generated. Comparison of the expected and detected lists identifies any mismatched nodes. Another method includes the step of setting a first pilot tone source to have a first pilot tone value. All other network pilot tone sources are set to have another pilot tone value. An optical path associated with the first pilot tone source is then mapped by identifying each node of the network having the first pilot tone value.

Abstract: A gateway exchange node according to a first embodiment of the present invention is disclosed. The gateway exchange node includes an exchange area network (XAN) xswitch. The gateway exchange node includes a wide area network (WAN) wavelength switch coupled to the XAN xswitch.

Abstract: An apparatus for replacing lost PSTN data in a packet network and for generating variable power white noise, includes a lost packet detection unit (402) for detecting lost data packets, a data processing unit (404) for producing in response a lost data output indicating when replacement data needed, data playout unit (408) or data replacement unit (406), each may be implemented as a variable power white noise generator (FIG. 3) to generate replacement data by reusing data stored in an extended playback buffer, and placing the re-used replacement data on an external network.

Abstract: Methods and apparatus for processing a received voice signal from a variable-delay network by a communications system that has at least one echo canceller. An echo canceller determines delay characteristics that are associated with the received voice signal and correspondingly modifies echo cancellation processing. In a variation of the embodiment of the invention, a first echo canceller sends silence descriptor information to a second echo canceller. The second echo canceller reconstructs a voice signal based upon the silence descriptor information and excitation vector information.

Abstract: A method and apparatus for discovering network paths sets a bit, normally used for purposes other than tracing a network path, in an overhead portion of a signal for causing state changes at nodes along a network path. The state changes are correlated with information about the signal to determine link connectivity between nodes to identify the network path. In a network of DS3 circuits, a non-critical alarm bit is set in a signal to transmit Remote Alarm Indications (RAI) which activate alarms at nodes of the network path. A response signal from the nodes can be sent through a network to a main node for correlation purposes. The method of discovering network paths can be used to update network path databases of network carriers and can be offered as a service to network carriers.

Abstract: A laser driver outputs a data protocol signal as controlled by an extinction control signal. The data protocol signal has a header including first and second bit patterns. A laser outputs an optical signal in response to being excited by the data protocol signal. The first and second bit patterns are measured and used to calculate an extinction ratio. The calculated extinction ratio is compared with a desired extinction ratio to generate the extinction control signal.

Abstract: A protocol for intra-shelf exchange of SONET/SDH line and path alarm, and section and line digital cross-connect information is disclosed. The protocol encompasses a method including continual monitoring each SONET/SDH datapath channel for alarms by one or more line cards (e.g., optical line interface, electrical line interface), processing the results of the channel monitoring to consolidate and encapsulate SONET/SDH alarm data by the line cards, forwarding this data to a switch card, which makes switching decisions based on the data. The SONET/SDH line, path, and equipment fault information may be collected, filtered, and prioritized by the line cards with some knowledge of the protection scheme(s) being implemented by the switch card, and may be formatted into an efficient encoding of the quality of each path.

Abstract: A switch core is set forth that comprises a plurality of duplex switches that are interconnected with a interconnection fabric to implement, for example, strictly non-blocking operation of the switch core for reciprocal traffic. In one embodiment, an N-way reciprocal switch is implemented. The N-way reciprocal switch comprises a plurality of duplex switches numbering N of at least a 1×(N?1) switch type (e.g., the duplex switches have at least N?1 ports available for connection to implement the interconnection fabric). The interconnection fabric interconnects the plurality of duplex switches so that each duplex switch is connected to every other duplex switch used in the interconnection fabric by a single connection. A similar architecture using switches numbering N of at least a 1×N switch type are also set forth.

Abstract: A receiver includes an I-Q demodulator (135) responsive to the I and Q components carried on a first frequency signal line (132). A demodulator frequency generator (275) generates a demodulating signal to extract the carried I and Q components. A phase adjustment circuit (105) makes the demodulating signal substantially in phase with the first frequency signal. A transition detector (445) generates a state transition signal in response to a change of state of at least one of the I and Q signals. A peak detector (460) generates a peak detected signal in response to occurrence of a peak amplitude of at least one of the I and Q signals. A clock generator (470) adjusts the phase of a symbol clock signal used to decode the I and Q components in response to the state transition signal and peak detected signal.

Abstract: A star communication network including a hub node (102) and links (102E) couple to the hub node for carrying data along routes in W channels. The hub node has switches connecting each channel of a first one of the links to various channels of a second one of the links through the hub node.

Abstract: In a network environment, a first master timing generator generates a first frame reference signal and a second master timing generator generates a second frame reference signal. A first data source generates a first data source signal, a first frame source signal, and a first clock source signal in response to a selected one of the first and second frame reference signals. Similarly, a second data source generates a second data source signal, a second frame source signal, and a second clock source signal in response to a selected one of the first and second frame reference signals. A timing recovery circuit generates a recovered reference signal and a recovered clock signal in response to a selected one of the first and second frame reference signals. A phase aligner stores the first data source signal in response to the first frame source signal and the first clock source signal.

Abstract: An optical signal having optical energy is received at an optical amplifier. The optical signal may be separated into a low frequency segment and a high frequency segment. The high frequency segment and the low frequency segment may be processed in order to determine a low frequency error signal and a high frequency error signal. The low frequency error signal may be summed with the high frequency error signal in order to generate a total error change associated with the optical amplifier.

Abstract: A multi-point communication system that comprises a head end unit disposed at a primary site and a plurality of receivers disposed at remote sites. The head end unit includes a transmitter for transmitting OFDM/DMT symbols over a predetermined number of bins across a transmission medium. The OFDM/DMT symbols are transmitted in periodically occurring formatted symbol frames. The cyclic prefix includes a predetermined periodic signal superimposed thereon. The receivers receive the OFDM/DMT symbols over a subset of the predetermined number of bins from the transmission medium and use the superimposed signals to attain symbol alignment. In accordance with a further aspect of the present invention, the receivers apply a predetermined incremental phase shift to received samples corresponding to the received OFDM/DMT symbols to thereby compensate for phase shifts.

Abstract: An apparatus and method for estimating a time delay between two signals are provided. An original signal and a delayed signal are provided to an average magnitude difference processor for determining an average magnitude difference for a sum of samples representing an envelope of each of the respective original and delayed signals, each for a series of sample delays. The time delay between the two signals is determined as the sample delay which minimizes the average magnitude difference.

Abstract: A voltage potential at a selected one or more inputs is controlled in order to produce a gain associated with an optical amplifier. One or more characteristics associated with a feedback loop coupled to the optical amplifier may be stored. A signal may be communicated to identify the occurrence of an error associated with the feedback loop. A selected current value may be provided to an element such that the optical amplifier is restored to a state associated with the optical amplifier prior to the failure. The selected current value is based on one or more of the characteristics associated with the feedback loop.

Abstract: Methods and apparatus related to maintaining a pre-determined ratio of a pilot tone power and a total mean optical power of an optical signal are provided. One method includes the steps of detecting the AC and DC components of an optical signal having a pilot tone signal. An amplitude of the pilot tone signal is varied in accordance with a difference between a pre-determined value and a ratio of the AC and DC components. Another method includes the step of generating an optical signal in accordance with a DC bias and an AC bias corresponding to a pilot tone signal. The AC and DC components of the optical signal are detected. At least one of the DC bias and the AC bias is varied in accordance with a difference between a pre-determined value and a ratio of the AC and DC components. An apparatus includes an optical source providing an optical signal in response to a DC bias and an AC bias corresponding to a pilot tone signal.

Abstract: A data routing mechanism is disclosed. The data routing mechanism includes virtual output queues (VOQs), corresponding to a first input port, that store data to be sent to one of a first and second output port. The data routing mechanism includes VOQs, corresponding to a second input port, that store data to be sent to one of the first and second output port. The data routing mechanism includes a switch fabric that includes a plurality of buffers at crosspoints between the first and second input ports and the first and second output ports. The data routing mechanism includes a first input scheduler that transmits a first data from the VOQs corresponding to the first input port to one of the plurality of buffers based on lengths of the VOQs corresponding to the first input port and a credit state of the plurality of buffers.

Abstract: A multi-point communications system is set forth herein. The communications system includes a receiver and transmitter disposed at a primary site for communication with a plurality of remote service units disposed at respective secondary sites. The receiver of the primary site receives OFDM/DMT signals over a number of transmission bins. A transmitter at the remote service unit includes an improved transmitter architecture. The transmitter comprises a first circuit for converting a signal into a first serial digital data stream and a second circuit for generating a second serial digital data stream from the first serial digital data stream of the first means. The second serial digital data stream is a digital representation of an OFDM/DMT signal that is to be transmitted to the receiver of the primary site and is generated from the first serial digital data stream through a modulated direct digital synthesis thereof.

Abstract: A digital cross connect includes a first transport switch that grooms inbound traffic for at least one local switch and a second transport switch that grooms outbound traffic for the local switch(es). The transport switches may operate independently. The local switch(es) may be protocol switches. The digital cross connect may be deployed in a central office in an electrical, optical, or wireless network.