Abstract: A fiber quadrupler device and method multiplexes the four optical fibers in a synchronous optical network (SONET) ring into a single linking fiber for full duplex optical transmission. The fiber quadrupler device optically couples two of the SONET fibers to a transmit converter for communications of downstream data from the SONET ring to a network element linked to the quadrupler by a single linking fiber. Two other SONET ring fibers are optically coupled to a receive converter for communications of upstream data from the network element over the single linking fiber to the SONET. An optical transceiver processes and directs the downstream and upstream signals to the receive and transmit converters. Either subcarrier modulation (SCM) or wavelength division multiplexing (WDM) is used in the receive and transmit converters.
Type:
Grant
Filed:
October 22, 1999
Date of Patent:
July 22, 2003
Assignee:
Adtran, Inc.
Inventors:
Fred Chu, Kevin W. Schneider, Peter O. Brackett, W. Stuart Venters, Steven R. Blackwell
Abstract: A mounting system is provided whereby a data communications system can be mounted in a plurality of different ways in one or more standard size rack openings and on planar surfaces. A first bracket selection and arrangement provides side by side dual mounting of two closures within a first rack having a first rack width. A second bracket selection and arrangement provides side by side dual mounting of two enclosures within a second rack having a second rack width greater than the first rack width. A third bracket selection and arrangement provides a single mounting of one enclosure in the first rack. A fourth bracket selection and arrangement provides a single mounting of one enclosure in the second rack. A fifth bracket selection and arrangement provides a single mounting of one enclosure on a planar surface.
Abstract: A power supply system has redundant regulated power supplies, whose output ports are diode-ORed to an output node. One of the power supplies outputs a regulated output voltage that is sufficient to meet current demand of a load coupled to the output node. Each power supply has an associated monitoring circuit that monitors the voltage drop across its OR-ing diode. The monitoring circuit for a non-dominant power supply controls its operation so that the non-dominant supply provides a reduced current through its diode to the output node that is less than the current demand of the load, but sufficient to forward bias the diode, and thereby enable the non-dominant supply to immediately respond to a load change, such as an interruption in the operation of the dominant power supply.
Type:
Application
Filed:
January 16, 2002
Publication date:
July 17, 2003
Applicant:
ADTRAN, INC.
Inventors:
Erik Stefan Bahl, John S. McGary, Jason P. Lyon
Abstract: A control link establishment code sequence for interrogating a network element interface (NEI) device terminating a local digital data services loop of a telecommunications network has an in-band code exclusive of codes currently employed to represent functional operations to be executed by a channel unit. Once a virtual link is established, a command—response mode session is conducted. To provide for byte alignment over the local loop for remote provisioning protocol employed at various violation mode rates, each command—response code byte is repeatedly transmitted, and a ‘delimiter’ byte is interleaved with successively repeated ones of the same code byte. Response messages from the NEI device also have code repeats interleaved with the delimiter byte.
Abstract: A sub (half)-rate DDS channel transport network architecture is configured to drive each of a ISDN transceiver unit of an OCU DP at one end of a two-wire path and the ISDN transceiver unit of a DDS termination unit at an opposite end of the two-wire path at one-half the normal clock rate, which reduces the operating frequency for rates of 56 kbps and 64 kbps. This sub-rate operation decreases its vulnerability to interference sources such as bridge taps. It also offers a trade-off against loop loss, enabling the effective range of the two-wire DDS circuit to be geographically extended, while complying with applicable industry standards for loop deployment and testing.
Abstract: A byte boundary information recovery mechanism locates the first bits of respective bytes of an asynchronous transfer mode (ATM)-based serial data stream, used by a frame synchronization mechanism to delineate respective cells of the ATM stream, and thereby enables transceiver equipment to successfully receive and parse ATM traffic. The invention employs a counter offset-based scheme that generates an output signal in potential alignment with the (first bit) boundary of a byte of the data stream, in response to the contents of a counter reaching a prescribed count value. It then iteratively shifts, as necessary, the bit time at which the output signal is produced relative to the counting operation of the counter, until the output signal is aligned with the boundary of a byte of the data stream.
Type:
Application
Filed:
January 2, 2002
Publication date:
July 3, 2003
Applicant:
ADTRAN, INC.
Inventors:
Jonathan Aaron Wright, Christopher A. Otto
Abstract: An embedded operations channel (EOC)-based signalling mechanism is incorporated within transceiver interface (U-BR1TE) components of an integrated services digital network (ISDN) telecommunication system, for effecting a relatively fast, warm start reactivation of a previously deactivated extended ISDN link between an ISDN switch and customer premises equipment. In response to the EOC-embedded ‘wake-up the loop’ message, the receiving U-BR1TE card supplies a 10 Khz wake-up tone to its associated termination equipment (either to the NT-1 in the case of a switch-sourced reactivation, or to the ISDN switch in the case of an NT-1 sourced wake-up request), to reestablish the ISDN loop.
Abstract: A power management system is interfaced with both a local utility power source and a remotely powered span, and monitors the power availability for and requirements of DDS terminal equipment. Upon detecting that local utility power is insufficient to operate the terminal equipment, a power limited converter derives power from the phone line. The span power drawn is limited to a fixed value that prevents the line from collapsing. An auxiliary capacitor stores energy from either local utility power or the span, to provide for periods of extended power operation (including ringing the phone).
Type:
Grant
Filed:
August 20, 1999
Date of Patent:
June 24, 2003
Assignee:
Adtran Inc.
Inventors:
Ralph R. Boudreaux, Jr., Steven M. Robinson, John S. McGary, Paul G. McElroy
Abstract: A loop loss measurement and reporting mechanism for a digital data services unit obviates interaction with a test unit at a far end of the loop, by relying upon a priori knowledge of the signal power and spectral content of a data port at the far end of the loop to conduct threshold detection and power level measurements. A received signal is amplified by amplifier circuitry, the gain of which is controllably adjusted by the microcontroller based upon the outputs of threshold detectors and power level measurement circuitry that monitor the amplified received signal. A front panel display is controlled by the microcontroller to display loop loss parameter information. To measure and report loop loss, the digital data services unit turns off its transmitter for a prescribed period of time and monitors an in-band signal of known power and spectral content sourced from the far end of the loop.
Abstract: An apparatus and method are disclosed for providing backup power over communication wires from a central office of a service provider to a remote customer premise. In accordance with the invention, a high voltage direct current (HVDC) power signal and a digital data signal are combined and coupled to the communication wires at the central office. The combined signal is then transmitted along the communication wires to the remote customer premise. At the customer premise, the HVDC power signal is separated from the digital data signal. The HVDC power signal is then down converted into a low voltage direct current (LVDC) power signal that is coupled to premise communication wires at the remote customer premise. The premise communication wires them provide a path for the data signal and the LVDC power signal to the customer premise equipment (CPE). Thus, a reliable and safe source of backup power is provided for the CPE over existing communications wires.
Abstract: The present invention provides a slope equalizer for use in a voice frequency channel card, which is preferably electronically and remotely controllable, and retrocompatible with existing telecommunication systems. The slope equalizer of the invention includes a high-pass filter followed by a variable gain stage amplifier, where the variable gain stage amplifier is an operational amplifier with a plurality of parallel input signal paths, each of the signal paths being a series-connected resistor and switch. The switch is preferably a FET transistor that is electronically and, optionally, remotely controllable. The circuit topology allows the use of FET transistors having relatively high on-resistances. A further advantage of the topology is that the FET switches are connected to a virtual ground by way of an operational amplifier, thereby reducing on-resistance modulation caused by signal variations across the FET.
Abstract: An in-band communication scheme reports the results of loop performance measurements from a remote site to a test site, by deliberately injecting, into a loopback sequence of a repeated code word, a selected one of different numbers of errors. The number of errors is selectable from among a plurality of different quantification values, based upon in which of a plurality of respective ranges of loop performance parameters, measured parameter values fall. The error data is thus effectively a gray-scale type of quantification of loop performance measurement data.
Type:
Application
Filed:
December 5, 2001
Publication date:
June 5, 2003
Applicant:
Adtran, Inc.
Inventors:
Martin Garza, Joe Luna, Mark Jefferies Ogden, James Ernest Owen, James Denson Wilson
Abstract: A synthetic impedance telecommunication line driver has no electrical energy-dissipating elements in series with its output, and synthesizes its output impedance in accordance with current fed back from an output current (mirror) sensing circuit. This allows the driver to realize substantially reduced power requirements for driving a telecommunication line, such as, but not limited to a DSX-1 line. The driver includes an operational amplifier having a first polarity input coupled through an input resistor to an input port, to which a signal voltage to applied to an output port is coupled. A second polarity input of the amplifier is coupled to a reference voltage. A feedback resistor is coupled between the amplifier output and its inverting input. An output current-dependent current source, such as a current mirror coupled in circuit with the output node, generates a current as a small fraction k of the output current.
Type:
Application
Filed:
November 29, 2001
Publication date:
May 29, 2003
Applicant:
ADTRAN, INC.
Inventors:
Daniel M. Joffe, Robert E. Gewin, Christopher J. Foran
Abstract: Adaptive clock recovery for the receiving entity of a communication system transporting constant bit-rate (CBR) services over an asynchronous transfer mode (ATM) or ATM-like network is performed by a digital phase locked loop (DPLL). The recovered clock is based on the DPLL's phase detector's count of high frequency service clock cycles between transitions in an input signal representative of instances of receipt of ATM cells subject to cell delay variations through the network, and a reference clock signal whose frequency is a prescribed fraction of that of the output clock. The DPLL's VCO function is an increment/decrement of the service clock frequency, which avoids constraining the operation of a high performance modem (such as a V.90 modem).
Type:
Application
Filed:
October 31, 2001
Publication date:
May 1, 2003
Applicant:
Adtran, Inc.
Inventors:
Bruce Edward Mitchell, Ayman K. Ghobrial
Abstract: A method and apparatus for driving the DC output of a precoder in the transmitter of a data communication system to zero after the end of a scheduled transmission of data include the use of a DC canceling circuit in a feedback arrangement with the precoder to drive the DC output of the precoder and of the transmitter circuits associated therewith to zero.
Abstract: A called telephone number substitution mechanism is incorporated into the call-routing software employed by the microcontroller of a customer premises-installed communication device, through which digitized voice and data services are supplied to a customer site. The number substitution mechanism automatically selectively modifies digits of an original (dialed) telephone number, as necessary, to conform with the connectivity requirements of the communication link serving the destination device, thereby enabling the call to reach the destination device.
Type:
Application
Filed:
October 16, 2001
Publication date:
April 17, 2003
Applicant:
Adtran, Inc.
Inventors:
Michael F. Lamy, Paul Graves McElroy, Charles A. Wilson, Arthur Edward Aldridge
Abstract: A redundant communication system contains a principal transceiver and a back-up transceiver to be controllably substituted for the principal transceiver. A monitor protection switch, which controls swapping the two transceivers, has an RF loopback test circuit that is switchably coupled to whichever transceiver is the backup. The RF loopback test circuit monitors the operational capability of the back-up transceiver, and provides an indication of its functionality. If the back-up transceiver is defective, corrective action can be taken in advance of a potential operational failure of the principal transceiver. As long as the RF loopback test circuit indicates proper operational capability of the back-up transceiver, the redundant transceiver can be immediately switched in place of the principal transceiver.
Abstract: An RF loopback test circuit is adapted to be coupled to an antenna port of a digital radio, to determine whether the radio is functioning properly. A frequency generator outputs an auxiliary frequency corresponding to the sum or difference between the radio's transmit and receive frequencies. The auxiliary frequency is coupled to a Schottky diode mixer, which is also coupled to the input/output port. If the radio's transceiver section is operating properly, the sum or difference frequency output of the Schottky diode mixer will be passed by only the diplexer's narrowband receive path filter to the radio's receiver section. The mixer's sum frequency is blocked by the diplexer's narrowband filters. Therefore, if the receiver section provides an indication that it is receiving a sufficient signal level from the RF loopback test circuit, it can also be inferred that each of the transmitter and receiver sections is operating properly.
Abstract: An autobaud mechanism is executed by transceivers coupled to opposite ends of a communication loop, such as an extended range SDSL loop, to resolve the maximum data rate that can be supported by the loop, using signal power and quality measurements to first estimate the length of the SDSL loop and thereafter iteratively adjust baud rate and/or number of bits/per baud, as necessary, to realize an SDSL baud rate that will ensure error-free transmission over the loop.
Type:
Grant
Filed:
July 20, 2001
Date of Patent:
March 25, 2003
Assignee:
Adtran Inc.
Inventors:
Jon Thomas Zakrzewski, Robert Allen Barrett, Thomas L. Ballard, III, John B. Wilkes, Jr.
Abstract: A spread spectrum communication system for wirelessly transporting autonomously time-referenced telecommunication data couples the data streams to mutually synchronized multiplexers, outputs of which are encoded and applied to associated I and Q channel spreaders, which spread the respective multiplexed data streams using mutually orthogonal spreading code sequences. The resulting spread I-channel data streams are coupled to I and Q channel summing units outputs of which are applied to respective channels of a QPSK modulator and transmitted to a receiver site. At the receiver the QPSK signals are correlated in despreading correlators and then decoded and demultiplexed to produce data streams, corresponding to those applied to the transmitter.
Type:
Application
Filed:
September 7, 2001
Publication date:
March 20, 2003
Applicant:
Adtran, Inc.
Inventors:
David Paul Nelson, Anthony A. Goodloe, Michael D. Turner