Abstract: A half duplex device and signal processing method thereof. First, a signal detection unit of a signal detector of a half duplex device obtains a short-term power and long-term power. Next, a data update unit of the signal detector sets a short-term power threshold as a default threshold, determines whether the long-term power is greater than the default threshold, sets the short-term power threshold value equal to the long-term power value if the long-term power value is greater than the default threshold value, and provides smooth performance in a noisy environment.

Abstract: A DC/DC converter capable of preventing abnormal temperature increase in a power transistor. The DC/DC converter comprises a loop circuit, a power transistor, an abnormal high temperature detection circuit, and an abnormality processing circuit. The power transistor supplies an electric current to the loop circuit according to a control pulse signal. The loop circuit accumulates electromagnetic energy in an inductor when the electric current is supplied and generates a negative DC voltage by causing a loop electric current to flow by using the electromagnetic energy accumulated in the inductor when no electric current is supplied. The abnormal high temperature detection circuit detects a normal/abnormal state of temperature of the power transistor. The abnormality processing circuit switches the power transistor off when the abnormal high temperature detection circuit has detected that the temperature of the power transistor is abnormal.

Abstract: A distributed echo cancelling architecture is provided where echo-cancelling functions are performed at locations remote from devices receiving signals with echoes. The echo cancelling functions use a reference signal, which has been corrupted with the echoes at the devices, for echo cancellation. As echo canceller resources are located at a central system and not at each individual device, the echo canceller resources can therefore be shared between the devices.

Abstract: A telephone call information delivery system includes answering circuitry to answer a telephone call incoming from a service provider and to attain information input by a caller. The system further includes an information signal provider to provide at least one signal to deliver at least some of the attained information to a user. As an example, from the delivered information the user can decide whether or not to answer the incoming call. In another embodiment, the system further includes an alert signal provider to provide a signal to alert the user and an activator to receive instruction from the user. The information signal provider operates responsive to the activator. This embodiment answers an incoming call, attains information from the caller, alerts the user, the user then instructs the activator and the signal provider responds and delivers attained information to the user. The user then decides whether to answer the call.

Abstract: A community dialing circuit apparatus for IP phone and POTS phone is provided. The apparatus includes an IP phone system, a POTS phone system, an insulation system connected between the IP phone system and the POTS system, and a keypad connected to the IP phone system and the POTS system for inputting the phone number. When the city power is on and a phone number having a format of the IP phone number is inputted, the POTS phone is disabled and the IP phone is activated. When the city power is on and a phone number having a first format of the POTS phone number is inputted, the POTS phone is activated and the IP phone is disabled. When the city power is off and a phone number having a second format of the POTS phone number is inputted, the IP phone is turned off and the POTS phone is activated.

Abstract: A non-linear processor for managing a speech signal is disclosed. The non-linear processor includes an adaptive lattice filter that generates a prediction error from a residual echo of the speech signal, a signum non-linearity unit that generates an excitation component from the prediction error, an excitation signal mixer that generates an excitation signal from the excitation component and a noise component, an inverse lattice filter that generates a modified residual echo from the excitation signal, and a gain adjuster that adjusts a power of the modified residual echo.

Abstract: In a communication terminal apparatus such as a portable telephone, it is made possible to sound ring tones of good tone quality simply by using arbitrary music or the like. In a communication terminal that conducts radio communication with a predetermined station and incorporates a music or speech data reproduction function, ring tones according to selected data included in previously prepared data for ring tones is outputted in response to an incoming call when a first mode has been set, whereas ring tones according to data of a previously set section included in music or speech data stored in a reproduction function section is outputted, in response to an incoming call when a second mode has been set.

Abstract: A telephone set is provided that includes a control section that, when detecting an off-hook operation, instructs a tone generator and a codec to stop a transmission of an incoming call and simultaneously instructs, using an awaiting voice generation instructing function section, the tone generator to produce a signal voice informing an awaiting state and the codec to transmit it to a handset. At the same time, the control section generates an off-hook signal and transmits it to a packeting section. The off-hook signal is incorporated in the packet to be transmitted by the packeting section and is transmitted from a packet network interface to a packet network.

Abstract: A state machine for attenuating the transition into and out of NLP state to reduce voice clipping and to reduce echo leak in a voice over packet signal transmission. The state machine interposes two additional transitional states between the NLP active state and the NLP inactive state to eliminate the sharp transition of NLP activity. An NLP entering state is used to gradually reduce the mixing ratio of echo and voice to attenuate the transition from passage of echo in the NLP inactive state to the suppression of echo in the NLP active state. An NLP exiting state is used to gradually increase (ramping the change) the mixing ratio of echo and voice to attenuate the transition from suppression of echo in the NLP active state to passage of echo in the NLP inactive state.

Abstract: An apparatus, system and method for monitoring calls that have been forwarded to a network-based voice mail system (VMS). The VMS receives the forwarded call and sends a start of greeting signal at the beginning and an end of greeting signal at the completion of the voice message greeting to the central office switch. The switch sends an activate call monitoring data message and a call monitoring alert signal to the customer premises equipment (CPE). If the CPE is adapted for call monitoring and includes a speaker assembly, then the speaker assembly is engaged in response to the activate call monitoring data message, thereby allowing hands-free call monitoring. If the CPE does not include a speaker assembly, then the called party may activate call monitoring by lifting the handset in response to detecting a call monitoring alert from the CPE. While monitoring the call, the called party may intercept the call to speak with the calling party.

Abstract: A digital direct access arrangement (DAA) circuitry may be used to terminate the telephone connections at the user's end to provide a communication path for signals to and from the phone lines. Briefly described, a means for providing a proper hookswitch transition for a variety of international phone standards is provided. The invention may also be utilized with means for transmitting and receiving a signal across a capacitive isolation barrier. More particularly, a DAA circuitry may be utilized which satisfies many or all hookswitch transition standards without the use of additional discrete devices. The hookswitch transition standards may be satisfied by ramping down the current flowing through the hookswitch prior to transitioning the hookswitch state. In this manner the hookswitch current change as a function of time (di/dt) may be decreased. Thus, the current through the hookswitch may be actively controlled prior to switching the hookswitch from an off-hook condition to an on-hook condition.

Abstract: The amplitudes of a signal on the microphone input of a telephone and a signal on the line input of the telephone are compared with each other and with two thresholds. The comparisons are sampled and the samples control an up-down counter. The count in the counter is compared with two thresholds and the results of the comparisons are used to control at least two accumulators. A first accumulator counts consecutive comparisons having the same result and a second accumulator counts up or down in accordance with the comparisons. The counts in the first and second accumulators are logically analyzed to determine whether to receive or transmit. A plurality of samples defines a window, at the end of which the up-down counter is reset. The accumulators store data from a plurality of windows.

Abstract: A method and apparatus for an automatic ring again feature on a telephone set for a user that answers a telephone call not intended for that user is disclosed. If a user has answered an incoming telephone call not intended for that user, a “Ring Again” feature on the telephone set is activated. In response to the Ring Again feature being activated, parallel telephone sets will ring again to allow a different user to answer the call or, alternatively, another device, such as an answering device, to answer the call.

Abstract: A method and apparatus for enabling multiple protocol communication over a network are disclosed. A first circuit communicates first signals in a first frequency band using a first data protocol and attenuates second signals in a second frequency band using a second data protocol. The first data protocol supports a first modulation technique and a second modulation technique. A second circuit communicates the second signals in the second frequency band using the second data protocol.

Abstract: A system for updating filter coefficients for use with an echo canceller, a related method for updating filter coefficients and an echo canceller including the system or the method. In one embodiment, the echo canceller has a nonadaptive filter and an adaptive filter, the nonadaptive filter having nonadaptive filter coefficients and configured to develop a nonadaptive error signal as a function of the nonadaptive filter coefficients, and the adaptive filter having adaptive filter coefficients and configured to develop an adaptive error signal as a function of the adaptive filter coefficients. The system includes a monitoring subsystem configured to monitor a quality of the nonadaptive and adaptive error signals and a selection subsystem configured to select one of the nonadaptive and adaptive filter coefficients for use by the nonadaptive filter based on the quality of the nonadaptive and adaptive error signals.

Abstract: An adaptive filter is programmed with an algorithm based on a normalized Least Mean Squares (nLMS) algorithm that adapts each sample time. The algorithm is modified to be more efficient in a variety of DSPs by computing multiple errors, one per sample, before updating coefficients. The update equation utilizes the multiple errors to achieve adaptation at a similar performance to known nLMS algorithms that adapt each sample time but without the instability that is observed in low echo-to-near-end-noise ratio (ENR) input conditions. Varying the relaxation step size prevents divergence. The DSP utilizes either one or more MAC units.

Abstract: An adaptive unit that taps into an existing POTS line, DLC POTS line, DLC channel unit designed for sealing current outputs, or AC-DC transformer designed for sealing current output, to provide sealing current to a DSL circuit thereby avoiding having to deploy a separate sealing current unit to supply the desired sealing current to the DSL circuit. The adaptive unit, or sealing current derivation device, is preferably deployed at remote terminals thereby facilitating the offering of new DSL service, but may also be utilized in a central office.

Abstract: Overhead voltage is allocated in a telecommunication system among different AC signals, such as POTS, on-hook transmission POTS, PPM and XDSL signals, communicated between a telephonic switch and a user device. The allocation is based on the available overhead voltage, the condition, such as impedance, of the line carrying communications to the user, and which of the signals are to be communicated.

Abstract: A telecommunications apparatus that has a substantially box-shaped subrack having a back wiring board mounting a connector and a plurality of shell-type plug-in units inserted in the subrack so that a connector of each of the plug-in units is connected to the connector of the subrack, further includes a flexible, electrically conductive seal member elastically deformedly disposed between a lateral surface of the plug-in unit inserted into the subrack and an interior portion of the subrack so as to enclose both the plug-in unit connector.

Abstract: A central office modem (50) that includes the capability of single-ended loop testing (SELT) is disclosed. The modem (50) includes a digital signal processor (54), a codec (56), line driver and receiver circuitry (58), and a hybrid circuit (60), by way of which a subscriber loop (LOOP) can be driven and sensed. The line driver and receiver circuitry (58) may include a transformer (74a, 74b) for driving the loop (LOOP), or the output may be capacitively coupled. The line driver and receiver circuitry (58) includes active termination, by way of operational amplifiers (80a, 80b). Switches (82a, 82b; 84a, 84b) are provided to selectively enable and disable the active termination function, and to selectively bypass or include the hybrid circuit (60). This control of the line driver and receiver circuitry (58) provides the ability to calibrate out its own characteristics, providing high precision SELT measurements of the load impedance type, and of frequency domain reflectometry, and time domain reflectometry.