Abstract: To use high noise transmission lines, such as an electric wire, as the lines to transmit signals, it is imperative to reduce the level of signals. The present invention is provided with a sending signal generating means 10, which outputs converted data after converting an input signal into a plurality of carrier signals assuming values at such intervals on the axis of frequency that the frequencies may not interfere with each other. If an interfering noise with any one of the plurality of frequencies arises on the transmission line, removal of only a carrier of the noise frequency would leave the communication in a good condition. Furthermore, better results can be hoped for if the respective carrier signals are so arranged as not to interfere with each other or so arranged to intersect orthogonally with each other not only on the axis of frequency but also on the axis of time.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or a class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode.

Abstract: Method and arrangement for sensing and digitally transmitting analog output measurement variables of a plurality of transformers The invention relates to a method and an arrangement for sensing and digitally transmitting analog output measurement variables of a plurality of transformers to a protective unit or panel unit in which digital measurement variables corresponding to the output measurement variables are transmitted to a data concentrator in which a telegram is formed with the digital measurement variables and a predetermined minimum sampling rate.

Abstract: Methods, apparatus and systems for multilevel data communication comprises dividing a set of information bits to be transmitted into a first group and a second group; encoding the first group to generate a block code, selecting a subset of symbols in a constellation of symbols in dependence on the block code according to a Gray-coded mapping function, selecting a symbol within the subset in dependence on the second group according to a Gray-coded mapping function, and transmitting the selected symbol.

Abstract: Described is a transmission system for transmitting a multilevel signal (xk) from a transmitter (10) to a receiver (20). The transmitter (10) comprises a mapper (16) for mapping an input signal (ik) according to a signal constellation onto the multilevel signal (xk). The receiver (20) comprises a demapper (22) for demapping the received multilevel signal (yk) according to the signal constellation. The signal constellation comprises a number of signal points with corresponding labels. The signal constellation is constructed such that Da>Df, with Da being the minimum of the Euclidean distances between all pairs of signal points whose corresponding labels differ in a single position, and with Df being the minimum of the Euclidean distances between all pairs of signal points. By using this signal constellation a significantly lower error rate can be achieved than by using a prior-art signal constellation.

Abstract: A nonlinear signal mapper that can implement any continuous one-to-one nonlinear map of baseband or intermediate-frequency digital signals. The mapping method follows a “divide-and-conquer” approach in that a nonlinear map to be implemented is piecewise decomposed into a set of simpler nonlinear component maps. The component maps are implemented using code-enabled feed-forward neural networks (FF-NNs). Each code-enabled feed-forward neural network only operates on samples of a digital input signal that lie in a specified interval of the real-valued number line. Code-enabled FF-NNs are controlled by code-words produced by a scalar quantization encoder. The quantization encoder also controls a multiplexer that directs values produced by the FF-NNs to the nonlinear mapper's output.

Abstract: An encoder structure for use in a DMT communications system, has a turbo encoder for encoding a portion of a data stream and generating a coded output. A data combiner has a first input receiving a remaining uncoded portion of the data stream and at least one further input receiving the coded output of the turbo encoder. A selector determines the portion of the data stream applied to the turbo encoder based on the data rate, latency requirement, coding gain performance and circuit complexity.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: A method is proposed for asynchronously transmitting a serial data comprises steps of: providing a first signal and a second signal, the first signal and the second signal having a state in a first interval; and keeping the state of the first signal and changing the state of the second signal into another state in a second interval for transmitting the serial data.

Abstract: The present invention comprises a method of obtaining coefficients for a transmit filter such that the power spectral density of the output for the different frequencies comes close to but does not exceed a maximum power spectral density of a communication(s) standard. By first doing a convex optimization procedure to obtain the autocorrelation coefficients for the filter and then using the autocorrelation coefficients to determine the filter coefficients, a low-order filter that closely approximates the desired output power spectral densities can be produced.

Abstract: An apparatus for compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter for non-linearly high-power amplifying a baseband signal by a high-power amplifier after quadrature modulation having a distortion extractor for extracting a non-linear distortion component from the nonlinearly high-power amplified modulated signal. A quadrature modulator quadrature-modulates the non-linear distortion component into a baseband distortion component after phase adjustment. A distortion overlapping section overlaps the baseband signal with a phase-inverted distortion component of the baseband distortion component. A converter converts the non-linear distortion component output from the distortion extractor into a DC component. A controller automatically controls an attenuation of the output signal of the high-power amplifier to minimize the DC component output from the converter.

Abstract: A branched power amplifier circuit includes two or more amplifier segments or branches, each with a corresponding lossy modulator. The branched power amplifier may be dynamically resized by enabling different ones of its branches, to deliver peak efficiency at a number of different amplifier output power levels. Each amplifier branch operates in a saturated mode and selectively amplifies an RF input signal. The lossy modulators provide either supply voltage or supply current modulation to corresponding amplifier branches, thus imparting highly linear amplitude modulation to the overall output signal generated by branched power amplifier, despite its saturated mode operation. The branched power amplifier circuit may be configured such that particular combinations of segments have peak efficiencies matched to the needs of one or more air interface standards used in wireless mobile communication systems.

Abstract: Communications systems, and particularly portable personal communications systems, such as portable phones, are becoming increasingly digital. The tendency towards digital systems has come about, in part, because digital systems may operate on less power than their analog counterparts. One area that has remained largely analog, however, is the modulation and RF amplifier circuits. To produce a RF frequency waveform a class D switching type amplifier is used. The output of the class D amplifier is coupled to an integrator, to create an analog signal. The analog signal coupled to a resonant circuit, to shape the output waveform into a sinusoidal RF broadcast signal. The waveform of the class D amplifier is duty cycle modulated by a combination signal representing the combination of desired amplitude modulation of the broadcast signal and the desired average power level desired.

Abstract: A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that is configured to output a message signal, and an encoder that is configured to generate a code word in response to the message signal. The code word is based upon a stacking construction that is generalized for the communication channel. The communication channel is characterized as a multi-input multi-output (MIMO) block fading channel. The transmitter also includes a modulator that is configured to modulate the code word for transmission over the communication channel. Further, the transmitter includes a plurality of transmit antennas that are configured to transmit the modulated code word over the communication channel. The system also includes a receiver, which has a plurality of receive antennas. The receiver is configured to receive the transmitted code word via the plurality of receive antennas.

Abstract: The present invention provides methods and apparatus to stably separate and extract an original signal from multiple signals by a few calculation steps when multiple signals have been observed in a mixed state. In an example embodiment, signals are separated by introducing a function having a monotonously increasing characteristic like an exponential type function as a cost function, and applying an adaptive algorithm that minimizes that cost function in terms of a signal separation matrix. Then, an error signal e(t) is calculated based on y(t) formed by this nonlinear function, the estimated separation matrix w(t−1) estimated at the previous cycle, and the observed signal x(t) at that time. Then, based on the calculated error signal e(t), the update of the separation matrix W(t) at that time is performed such that consideration weight is increased when estimation errors are large using the cost function having a monotonously increasing characteristic.

Abstract: Improved carrier recovery and symbol timing systems and methods suitable for use in connection with a dual-mode QAM/VSB receiver system is disclosed. Carrier and symbol timing acquisition and tracking loops are phase/frequency locked to an inserted pilot signal provided in an input VSB spectrum at a given frequency. An input spectrum is centered about baseband and the pilot is extracted by an equivalent filter which functions as a bandpass filter having pass bands centered about the pilot frequency. Since the pilot signal's frequency is given, its position in the frequency domain for any sampling frequency, is deterministic. The receiver's sampling frequency is provided such that the relationship is expressed as fc=fs/4. When tracked by a phase-lock loop, the pilot signal will appear at the correct location in the spectrum if the sampling frequency fs is correct, and will be shifted in one direction or the other if the sampling frequency fs is too high or too low.

Abstract: The apparatus measures timing variations, such as the jitter or wander in a timing signal (100) of a telecommunications network. A recovered clock signal is sampled and digitised to produce a series of digital clock samples which are then processed (135) with reference to a local digital reference signal to produce digital baseband frequency in-phase (I) and quadrature (Q) components (165, 170) these being further processed (145) to produce the digital phase information of said clock signal to determine (175) the required parameters of the network. The step of digitally processing said clock samples with reference to a local reference signal can be conveniently and cheaply implemented using a digital signal down-converter IC (135), for example of a type existing for digital radio receiver implementations. For jitter measurement, the local reference signal may be generated by a phase-locked loop (as in FIG. 2). For wander measurements an external reference clock is used (as in FIG. 3).

Abstract: Performing channel estimation with a limiting receiver includes performing a first estimation of a first portion of a signal to obtain first parameters of the portion of the signal. The first portion of the signal has predetermined offsets added during transmission. The predetermined offsets are based on the modulation format of a second portion. The first and second portions have different modulation formats. The first portion of the signal is demodulated using the first parameters to recover data symbols. An equalizer is trained using a decision directed technique to obtain equalizer coefficients. The demodulated first portion of the signal is checked to confirm correct demodulation. The second portion of the signal is then demodulated using the equalizer coefficients.

Abstract: A turbo decoder system (1) for decoding turbo coded bits, is provided with a system input (2) and a plurality of turbo decoders (3; 3-1, . . . 3-n) each having a turbo decoder input (4; 4-1, . . . 4-n). The plurality of turbo decoders (3; 3-1, . . . 3-n) is arranged in parallel, and the system (1) is further provided with an allocating device (6) coupled between the system input (2) and the turbo decoder inputs (4; 4-1, . . . 4-n) for dynamically allocating the turbo coded bits to one of the turbo decoders (3; 3-1, . . . 3-n).

Abstract: Detection and identification of known sequences such as sequences composed of Walsh-Hadamard sequence and scrambling sequence are provided in a fast fading and frequency offset environment using a segmented correlator and FHT (Fast Hadamard Transform) architecture with frequency offset compensation. The incoming sequence of samples or data is segmented into blocks. Each block is individually detected using a correlator/FHT segment. Each sequence identifying output of each correlator/FHT segment is multiplied by a sinusoid for frequency offset compensation. The frequency offset compensated output from each correlator/FHT segment is summed with the corresponding frequency offset compensated output of other correlator/FHT segments. Each sum is compared with a threshold to determine whether a particular sequence has been detected and identified.

Abstract: Analog processing sections (3a to 3b) generate base band analog signal from the received signal. A/D converting sections (4a to 4b) the outputs of the analog processing sections into digital signals. Soft-decision output equalizers (11a to 11b) make soft decisions on the digital signals. A combining section (12) combines the results of the soft decisions to output a soft-decision value. An error correcting section (13) performs error correction processing with respect to the soft-decision value.

Abstract: A method is provided for synchronizing distributed processors. The method comprises determining a desired number of offset values between two processors, wherein each processor comprises a quartz crystal, determining parameters of a regression line, wherein the regression line is a function of the offset values over the desired number of offsets, and adjusting a synchronization interval according to the parameters.

Abstract: In a communication system in which an incoming signal is pulse shaped prior to detecting the information bearing point of the signal, processing overhead can be significantly reduced by only processing the sample points corresponding to the information bearing point and two points bounding the information bearing point. During signal acquisition, the signal is over sampled and the pulse shaping filter processes every sample point, or every Nth sample point in the case of down sampling. Once the sample point corresponding to the information bearing point is determined, the pulse shaping filter can be instructed to only process the sampling corresponding to the information bearing point and two neighboring samples. The system and method is adaptive, in that the samples that are processed can shift as the information bearing point shifts relative to the sample points. This is accomplished by re-synchronizing the timing of the received slot.

Abstract: A method and apparatus for high-resolution jitter measurement. A signal generating circuit produces a period reference signal and applies the reference signal to a sampling input of an ADC. An output signal of a DUT is coupled to a clock input of the ADC, and the frequency of the reference signal is set to be equal to the frequency of the output signal of the DUT plus a fixed offset such that the code output provides a digital representation of a beat signal. The beat signal is defined by discrete sampling points representing at least ten periods of the beat signal. Each period of the beat signal comprises a respective subset of the sampling points, wherein the sampling points of each of the subsets correspond to unique sampling phases that are defined similarly for each of the periods of the beat signal by the offset. The sampling points of each of the subsets are subject to variation from the corresponding sampling phases as a result of the jitter.

Abstract: The present invention relates to a method of inserting sync patterns of different lengths in modulated data, and a recording medium having sync patterns produced by said method. The sector sync and the frame sync pattern to be inserted in modulated data in accordance with the present invention must satisfy the given (d, k) constraints, have distinctive 0's run the modulated channel data can not have, and be as short as it can. In addition, the frame sync pattern is shorter than the sector sync pattern because the frame sync pattern is more frequently inserted than the sector one. Owing to the present sync patterns, the storage capacity reduction of a recording medium due to necessary insertion of sync patterns can be minimized under a given modulation condition.

Abstract: The invention refers to an apparatus for generating a reference frequency depending on a timing information extracted from a data stream. In order to generate a carrier frequency in a user station of a satellite TDMA network at low costs which is accurate and stable and which meets stringent phase noise requirements, it is suggested to use at least one free-running oscillator. The frequency deviation with regard to the timing information extracted from the data stream is estimated by an estimation means. At least two oscillation signals are derived from the at least one oscillation means and are linked together by a linking means yielding said reference frequency. A frequency correction value is applied to at least one of the oscillation signals such that the timing information given by the reference frequency corresponds to the timing information extracted from said data stream.

Abstract: The invention relates to methods and apparatus that receive an integration result, receive logic states of data bits corresponding to the integration result, and perform a high-speed multiplication operation. Embodiments of the invention selectively multiply the integration result according to the logic states of the corresponding data bits. Advantageously, relatively large integration results corresponding to data bit transitions that do not include a change of logic states, such as logic 0 to logic 0 or logic 1 to logic 1, can be multiplied by zero (0). Relatively smaller integration results corresponding to integrations of data bit transitions including a change in logic states, such as from logic 0 to logic 1 or from logic 1 to logic 0, can be multiplied by one (1) and by negative one (−1).

Abstract: A phase-locked loop (PLL) frequency synthesizer incorporates fractional spur compensation circuitry. This fractional spur compensation circuitry dynamically compensates charge pump ripple whenever a charge pump operates. It can utilize a programmable divider, two phase detectors each using a charge pump stage pumps. A fractional accumulator stage determines the number of charge pumps that operate during a phase comparison. The PLL frequency synthesizer avoids the need for compensation current trimming. Also, fractional compensation is accomplished dynamically and in a manner that is robust to environmental changes.

Abstract: A phase-locked loop (PLL) fractional-N type frequency synthesizer incorporates a sample-and-hold circuit. The synthesizer can reduce circuit size by eliminating a loop filter. Further, the synthesizer can incorporate fractional spur compensation circuitry to compensate charge pump ripple whenever a charge pump operates. The synthesizer or fractional-N type PLL can use a divider and at least two phase detectors coupled to a sample-and-hold circuit. A lock detecting circuit can initially determine a reference voltage for the sample-and-hold circuit. Also, fractional compensation is accomplished dynamically and in a manner that is robust to environmental changes while a control voltage is stably maintained for the voltage controlled oscillator.

Abstract: A unified serial link system and method for transmitting digital data across wired media including a transmitter and a receiver. The system comprises a phase locked loop (PLL) control circuit, a phase rotator circuit, a phase buffer circuit, and an equalization driver circuit. The phase rotator circuit is configured to acquire a clock phase from the phase locked loop control circuit and modulo shift the clock phase into a desired phase angle. One embodiment comprises a dual loop PLL having a digital coarse loop and an analog fine loop, a multi-stage voltage controlled oscillator, a voltage comparator, a PLL control logic, a digital to analog counter and a low pass filter. The fine loop includes the oscillator, a frequency divider, a phase-frequency detector, a charge pump and a loop filter.

Abstract: Surfaces of the structural components of a nuclear power plant exposed to reactor water are wetted with an electroless plating solution containing an electrical insulating substance. The electrical insulating substance has a high resistivity about 105 (100000) times those of the structural components of the nuclear power plant or above. A metal film containing the electrical insulating substance is formed on the surfaces of the structural components exposed to the reactor water by wetting the surfaces of the structural components with the electroless plating solution. Thus, the electrochemical corrosion potential of the structural components is reduced regardless of whether hydrogen is injected into the reactor water.

Abstract: The present invention relates to a method for inhibiting stress corrosion cracking occurring on steam generator tubes in the secondary side of nuclear power plants and an inhibitor therefor. The method comprises supplying cerium boride as an inhibitor for stress corrosion cracking into the secondary feed water of the nuclear power plants. The method according to the present invention improves resistance of stress corrosion cracking three times or higher than no inhibitor, and two times or higher than the conventional inhibitor. In particular, the method according to the present invention shows a superior inhibiting effect in the lead-contaminated environment such that the complete inhibition of stress corrosion cracking can be achieved. As thus, the method can reduce the unexpected stop of operating nuclear power plants caused by the stress corrosion cracking on steam generator tubes, thereby reducing the cost required for maintaining and repairing the tubes.

Abstract: Fuel element and gas-cooled nuclear reactor using this type of fuel elements.

Abstract: Disclosed is a method for manufacturing a tube and a sheet of niobium-containing zirconium alloys for the high burn-up nuclear fuel. The method comprises melting Nb-added zirconium alloy to ingot; forging the ingot at &bgr; phase range; &bgr;-quenching the forged ingot after solution heat-treatment at 1015-1075° C.; hot-working the quenched ingot at 600-650° C.; cold-working the hot-worked ingot in three to five passes, with intermediate vacuum annealing; and final vacuum annealing the cold-worked ingot at 440-600° C., wherein temperatures of intermediate vacuum annealing and final vacuum annealing after &bgr;-quenching are changed so as to attain the condition under which precipitates in the alloy matrix are limited to an average diameter of 80 nm or smaller and the accumulated annealing parameter (&Sgr;A) is limited to 1.

Abstract: A fuel assembly having a plurality of fuel rods arranged in a square lattice array. The fuel rods include a plurality of short-length fuel rods each having a fuel active length shorter than that of each of remaining ones of the fuel rods. At least one water rod is arranged in a region in which one or more of the fuel rods are arrangeable in the array, and a plurality of fuel spacers are provided at a plurality of positions in the axial direction for holding the plurality of fuel rods and the at least one water rod, with mutual radial intervals therebetween being kept immovable. The plurality of short-length fuel rods include at least one first short-length fuel rod arranged in the outermost peripheral region of the square lattice array. Each of the plurality of fuel spacers include a plurality of cylindrical members.

Abstract: A duct-type spacer grid for nuclear fuel assemblies is disclosed. In this spacer grid, a plurality of duct-shaped grid elements, individually having an octagonal cell, are closely arranged in parallel and are welded together, thus forming a matrix structure. The grid elements do not pass across the center of the subchannel of the assembly, thus effectively reducing pressure loss. Each of the grid elements is formed as an independent cell, and so they effectively resist against a lateral impact. A plurality of integral type swirl flow vanes, having different heights or same height, axially extend from the top of the grid to be positioned within each subchannel. The swirl flow vanes are bent outwardly, and so they do not contact the fuel rods during an insertion of the fuel rods into the cells. In the spacer grid, the fuel rods are supported within the cells by line contact springs without using any dimple.

Abstract: One aspect of the present invention is a method for multisector computed tomographic (CT) imaging of a cyclically moving object, including steps of: helically scanning a cyclically moving object with a CT imaging system having multiple detector rows and a rotating gantry, at a gantry rotation speed selected either to lead or to lag a cycle of the cyclically moving object; retrospectively gating the projection data of the object with a gating signal related to the motion of the cyclically moving object so that a geometric phase difference is created between a cycle of the rotating gantry and the motion of the cyclically moving object; and reconstructing an image of the cyclically moving object using gated sector data from image data representing a plurality of consecutive cycles of the cyclically moving object.

Abstract: An illumination system comprises (a) a first optical element upon which a light beam impinges, where the first optical element has first raster elements that partition said light beam into light channels; (b) a second optical element that receives said light channels, where the second optical element has a second raster elements; (c) an object plane that receives said light channels via said second optical element; and (d) an exit pupil that is provided with an illumination via said object plane. The system is characterized by an assignment of a member of said first raster elements and a member of said second raster elements to each of said light channels to provide a continuous beam path from said first optical element to said object plane for each of said plurality of light channels. The assignment is changeable to provide an adjustment of said illumination in said exit pupil.

Abstract: A method of imaging an object that includes subjecting an object to a beam of radiation that is directed along a first direction and analyzing a first portion of the beam of radiation that is transmitted through the object along the first direction so that the intensity of the first portion is suppressed. Analyzing a second portion of the beam of radiation that is refracted from the object. Generating an image of the object based on the suppressed first portion of the beam of radiation and the second portion of the beam of radiation.

Abstract: A relocatable container inspection device, which is constituted by modularized units, is used for inspecting a container.

Abstract: An x-ray generation apparatus includes an x-ray reflecting mirror and x-ray generation part. The x-ray reflecting mirror is formed on an inner surface of a concave aspheric surface. The x-ray generation part receives at least one incident energy beam. The x-ray generation part is arranged near a focal point including a focal point of a paraboloid, and the x-ray reflecting mirror has at lest one aperture formed in a position except for a part of the concave aspheric surface crossing an axis including the focal point of the concave aspheric surface, and an incident energy beam irradiates the x-ray generation part through the aperture.

Abstract: An above-table transillumination device has been an X-ray radiator that can be rotated around the horizontal axis of the radiator stand and that has a swivel lock having a manually actuatable unlocking lever. The unlocking lever is arranged at the front side of the radiator carrier facing away from the radiator stand and is connected to the lever of the swivel lock via a transmission device.

Abstract: An X-ray imaging system has an X-ray head containing an x-ray source which emits an X-ray beam. The head is rotatable around a pair of orthogonal axes for orienting the emitted X-ray beam in space. A pair of head angle sensors are located with the X-ray head, each being associated with a different one of the pair of axes for measuring an angle of inclination of the X-ray head dependent on its rotation around its associated axis. A display is operably connected to each head angle sensor through a signal processing unit for providing a graphic displaying of angle information related to each of the measured angles collocated at a single viewing station.

Abstract: The invention is concerned with a method for controlling the transmission power for a session in a system for transmitting data via a telephone line by using a digital subscriber line between a user terminal and a central unit. In the method, the transmission power is increased or decreased between given limit values so that the power is kept as low as possible, while still providing sufficient transmission quality. The quality criteria according to which the transmission power is controlled consistis of the value of the Signal to Noise Ratio (S/N), and the number of bit errors BER within a given time interval.

Abstract: Systems for dialing an emergency telephone number from a teleworking client according to the invention include apparatus that implement the steps of detecting at a teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.

Abstract: Methods for dialing an emergency telephone number from a teleworking client according to the invention include detecting at the teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. The apparatus of the invention resides in software that is installed in off the shelf hardware. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.

Abstract: Methods for accurate transmission of ELIN/callback number from an emergency caller calling from behind a PBX/MLTS include assigning a port equipment number to each device/trunk of the PBX/MLTS and associating ports/devices with ELINs and callback numbers. The apparatus of the invention detects an emergency number, assigns the call priority, and uses the port/device number to determine the ELIN/callback number and properly transmit the ELIN/callback number over a private network for far-end hop-off to the public network PSAP.

Abstract: Methods for accurate transmission of ELIN/callback number from an emergency caller calling from behind a PBX/MLTS include prioritizing the emergency call, assigning a port equipment number to each device/trunk of the PBX/MLTS and associating ports/devices with ELINs and callback numbers. The apparatus of the invention detects an emergency number, assigns the call priority, and uses the port/device number to determine the ELIN/callback number and properly transmit the ELIN/callback number.

Abstract: The invention is directed to methods for accurate transmission of ELIN/callback number from an emergency caller calling from behind a PBX/MLTS include assigning a port equipment number to each device/trunk of the PBX/MLTS and associating ports/devices with ELINs and callback numbers. The apparatus of the invention detects an emergency number, assigns the call priority, and uses the port/device number to determine the ELIN/callback number and properly transmit the ELIN/callback number optionally first over a private network and to the public network PSAP.

Abstract: The invention is directed to methods (and corresponding apparatus) for accurate transmission of an ELIN/callback number from an emergency caller after the emergency call goes on-hook. The methods include (upon initiation of an emergency call) the steps of storing an emergency location identification number and/or callback number in a buffer; and, upon detecting an on-hook event, transmitting the ELIN and/or callback number from the buffer. According to a preferred embodiment of the invention, the emergency call is disconnected after said step of transmitting; and prior to said step of transmitting, optionally first over private network and to the public network PSAP, a timer is initiated. The step of disconnecting is performed after the timer expires.