Matches 51 - 100 out of 191 < 1 2 3 4 >
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6128370 Multiple tone detection using out-of-band background detector  
A multiple tone detector includes n tone detectors, each detecting one of n distinct tones, where n≥2, and a background detector which generates a measure of accumulative background energy E avg ...
6115464 Method and system for distinguishing valid DTMF signals from spurious DTMF noise  
A method and system for distinguishing valid DTMF signals from spurious DTMF noise includes detecting signals having a first signal component indicative of DTMF signals and having a second signal...
6101252 CAS tone disguising method and apparatus  
The ADSI system 100 has a file stored in RAM 202 or ROM 204. The file plays a CAS tone. The CAS tone is disguised by playing one or more introductory tones as frequencies lower than the CAS tone....
6072782 Efficient echo cancellation for DMT MDSL  
An echo cancellation scheme for DMT MDSL digital subscriber loop telecommunications data transfer is disclosed. The echoed data stream frame is aligned with the incoming data stream frame. The time...
6049712 Arrangement system and method relating to telecommunications access and control  
An arrangement relating to telecommunication access and control. An arrangement is provided at least for providing access information for protected subscriptions to at least one telecommunications...
6038310 Service node for a telephony network  
Service node for use in a communications network for providing access to services available to callers using the network. The service node includes a plurality of peripheral devices, a switch for...
6031903 Method for expediting access to services on a switched communications network  
A method for providing access to services during communication between subscribers over a communication path on a switched communication network is provided. In a first step, the injection of a...
6021192 Tone detector  
A tone detector for detecting a multi-tone input signal in the presence of speech and noise, comprising first signal processors that generate output signals indicating the energy level of the input...
6014435 Unauthorized call defeat apparatus  
A call defeat device to prevent calling unauthorized numbers, such as long distance, 1-900 etc., which is adapted to prevent a caller from successfully dialing one or more predetermined digit...
6014441 Method and system for generation of tone signals over a transmission channel  
A user-authentication system includes an authorized user device (AUD) for transmission of dtmf tones to a user-verification system (UVS) over a telephone network, where user-verification is...
5995557 Tone detection with aliasing bandpass filters  
To detect a dual tone pair signal in a telephone communication system, the signal is sampled at the Nyquist frequency. The sampled signal is filtered to determine the top three tone frequency power...
5982874 Transmission system with improved tone detection  
In a transmission system a pair of signalling tone signals is transmitted by a transmitter (2) to a receiver (6) via a transmission channel (4). In the terminal (6) a tone detector is used to...
5978676 Inband signal converter, and associated method, for a digital communication system  
Apparatus, and an associated method, for converting an inband signal, such as a DTMF signal, into a form to permit transmission thereof to a receive station. An inband signal, such as a DTMF signal...
5949874 Method and system for compensating for signal deviations in tone signals over a transmission channel  
A user-authentication system includes an authorized user device (AUD) for transmission of DTMF tones to a user-verification system (UVS) over a telephone network, where user-verification is...
5937059 DTMF detector for detecting DTMF signals using a digital signal processing chip and method thereof  
A dual tone multi-frequency detector includes a pulse code modulation expanding unit for converting pulse code modulation data into linear data. A correlating unit constructed from a plurality of...
5913189 Voice compression system having robust in-band tone signaling and related method  
A communication system, and related method, for reliably transmitting DTMF code signals through a low-bit rate channel employing a VSELP speech compression algorithm. The system adds relatively...
5907597 Method and system for the secure communication of data  
A user-authentication system includes an authorized user device (AUD) for transmission of dtmf tones to a user-verification system (UVS) over a telephone network, where user-verification is...
5889851 DTMF signal detection/removal using adaptive filters  
An input digital sample containing voice and DTMF signal is used as an input to an adaptive filter. The output signal of the adaptive filter is used to generate a residue from the difference...
5862212 Method and structure for detecting a customer premises equipment alerting signal  
A method and device for detecting a customer premises equipment alerting signal (CAS) tone in a telephone system which has both caller identification and call waiting. The present invention...
5862210 Signal detection circuit and telephone apparatus  
A signal detection circuit includes band pass filters for detecting frequency components of a Call Alert signal (CAS) signal, a tone detection circuit for detecting whether or not a signal...
5818929 Method and apparatus for DTMF detection  
The total energy of a signal that has entered from a telephone line is detected before the signal is applied to an AGC circuit. After the signal is applied to the AGC circuit, the energy of a DTMF...
5809133 DTMF detector system and method which performs frequency domain energy calculations with improved performance  
An improved dual tone multifrequency (DTMF) or multitone signal detector which more efficiently detects DTMF signals. For each received frame, the present invention initially performs only a...
5793862 Information signal detection device and information signal detection method  
An information signal detection device and an information signal detection method are disclosed with which it is possible to transmit information by means of a DTMF signal using a channel that is...
5768356 User programmable personal call manager  
With a personal call manager, when a caller calls a primary telephone number for the owner of the personal call manager, the personal call manager selectively routes the incoming call to any...
5737331 Method and apparatus for conveying audio signals using digital packets  
A digital telecommunication network (10) provides an audio processor (56) for each call in each external node (14). The audio processor (56) includes a vocoder and additional functions. At a source...
5729602 Programmable multi-tone voice message starting system  
A system for detecting the presence, in an audio channel which may contain voice signals, of a tone at a frequency selectable from among a plurality of selectable frequencies. A bandpass filter...
5706341 Active digit cancelling parallel dialer  
A method of dialing digits using dual tone multifrequency (DTMF) signals comprised of generating a digit from a DTMF generator comprised of a first pair of signals forming a DTMF signal, one signal...
5706328 Automated inbound test facility and method  
A technique is provided for enabling remote testing of a telecommunications service provided by an international gateway switch (12). To accomplish such testing, a test facility (10) associated...
5699421 Telephone answering device with low cost dual tone multi-frequency detector  
A telephone answering device (TAD) includes a remote access mode which is operative responsive to dual tone multi-frequency (DTMF) signals. At least three bandpass filters each receive an input...
5694461 Method for controlling long distance calling using a multi-frequency receiver  
A method for controlling long distance calling in an analog key telephone system having a multi-frequency receiver includes the steps of: connecting the multi-frequency receiver to a telephone...
5694466 DTMF detector system and method which performs improved twist computation and thresholding  
An improved dual tone multifrequency (DTMF) or multitone signal detector which more efficiently and reliably detects DTMF signals. The present invention performs twist computations only when the...
5687177 Tone blocking using variable delay buffer  
A tone blocking system and method for use preferably in conferencing systems in order to prevent control tones from being transmitted to other conferees is disclosed. The buffer length used to...
5659606 Programmable modular apparatus and method for processing digital signals and detecting telephone tones  
A circuit and method for detecting identification signals in a digital input signal (Rx) having signal parameter values which are provided to a signal memory (54). The values provided to the signal...
5638436 Voice detection  
In a voice processing system, a voice detection algorithm is disclosed wherein the sensitivity is adjusted based upon whether or not tones (e.g.; DTMF) are presently being received. In an...
5619564 Tone detector with improved performance in the presence of speech  
This tone detector which is suited for dual tone multifrequency (DTMF) digit detection, separates the pairs of tones into a low frequency and high frequency group in which the other frequency group...
5619565 Voice activity detection method and apparatus using the same  
A method for detecting the presence of voice, single tone and dual tone signals compares a ratio r which equals the square of the maximum value of the received signal (A max) during a sampling...
5592544 DTMF signal judging apparatus  
A DTMF signal judging apparatus includes a first power calculator, and second power calculator and a judging apparatus. The first power calculator calculates the overall power of an input signal or...
5583934 DC level control for an electronic telephone line card  
DC level control for an electronic telephone line card which filters the DC component from the input audio signal, determines the gain setting of the transmit path, develops a DC adjust voltage...
5579387 Apparatus for accessing function code in telephone  
An apparatus adapted to be activated by an input device for accessing a function code in a telephone comprises a first memory for storing a function code, a second memory electrically connected to...
5572588 Method and apparatus for detecting reception of a tone signal  
Tone detection may be accomplished by receiving an in-phase signal component 203 and a quadrature signal component 204. These components are then sampled to produce a plurality of sampled in-phase...
5535271 Apparatus and method for dual tone multifrequency signal detection  
A DTMF digit detecting method and apparatus includes signal state identifier (32) for identifying whether the received signal is in a DTMF-digit-detect state, a no-detect high-energy state, or a...
5530743 Telephone exchange apparatus and tone sending method in telephone exchange apparatus  
In a telephone exchange apparatus for performing exchange processing by a memory time switch, first tone signals are generated, and second tone signals are generated by sequentially...
5506885 Method of adapting processing parameters in a call processing system  
A method and apparatus for utilizing DTMF tones and supervisory tones in a call processing system to adjust parameters for future tones and/or speech. The tones initially received are analyzed to...
5495526 Tone-detection method for detecting at least one tone in a dual-tone multifrequency signal, call-progress method using the same  
A method for detecting the presence of single tone and dual tone signals compares a ratio r which equals the square of the maximum value of the received signal (A max) during a sampling period...
5479498 Digital line card having universal port for upgrading electronic messaging system  
A digital line card is provided for use in an electronic messaging system for enabling the receipt of voice and text or image data over a single communications port. The digital line card includes...
5459785 DTMF signal receiving circuit  
A DTMF signal receiving circuit which is capable of freely selecting a frequency of a received dial tone signal. The DTMF signal receiving circuit receives a DTMF signal, decodes the DTMF signal,...
5459781 Selectively activated dual tone multi-frequency detector  
A technique for improved DTMF detection utilizes a speech detector, either alone or in combination with other information from a voice processing arrangement, to adjust the sensitivity of the DTMF...
5459788 Apparatus for interfacing analog telephone in ISDN terminal adapter  
An apparatus for interfacing an analog telephone in an ISDN terminal adapter is able to independently perform call set-up regardless of a personal computer's operation, while being provided with...
5459784 Dual-tone multifrequency (DTMF) signalling transparency for low-data-rate vocoders  
Multifrequency signals are detected in a received signal by extracting filter coefficients from the received signal, generating line spectrum frequency (LSF) parameters from the filter...
5442696 Method and apparatus for detecting control signals  
The present invention provides a method and apparatus for detecting control signal information for an element of a communication system. The control signal information is included in one or more...
Matches 51 - 100 out of 191 < 1 2 3 4 >