Abstract: Method and apparatus for securing the transmission of DTMF signals by a telephone over a telephone line. If the telephone is operating in a mode wherein another party may hear any DTMF tone generated by the telephone, such as over the loudspeaker of a speakerphone or as part of a conference call, the telephone prevents generation of an audible signal which predictably corresponds to the actual DTMF value of any button pushed by the user.

Abstract: Method and apparatus for securing the transmission of DTMF signals by a telephone over a telephone line. If the telephone is operating in a mode wherein another party may hear any DTMF tone generated by the telephone, such as over the loudspeaker of a speakerphone or as part of a conference call, the telephone prevents generation of an audible signal which predictably corresponds to the actual DTMF value of any button pushed by the user.

Abstract: A call-center has agents using headsets, which are connected to a private business exchange (PBX). Noise cancellation occurs in a noise filter, within or connected to the PBX. Noise cancellation for a particular agent's conversation is achieved by receiving the voice signals from neighboring agents' headsets and by using adaptive noise cancellation in the noise filter to remove the other agents' conversations from the particular agent's conversation. Microphones may also be placed at other noise sources, such as HVAC equipment, so that offending noises are accurately received at the noise filter and removed from the agents' conversations.

Abstract: A method and apparatus are disclosed that seek to improve the quality of service that is experienced during the transmission of a stream of packets across one or more paths. In particular, a transmitting node encodes a source stream of data (e.g., audio, video, etc.) into one or more sub-streams, and distributes those sub-streams onto multiple network transmission paths. In accordance with the illustrative embodiment of the present invention, the transmitting node evaluates the quality of service of a first network path that fails to provide a quality-of-service guarantee. When the quality of service of the first network path becomes unsatisfactory, the coding of one or more sub-streams that are being transmitted on a second network path is adjusted. In other words, the coding on a second channel is adjusted in response to the changing conditions on a first channel.

Abstract: Methods and apparatus are provided for reducing echo from a received signal. A suppression gain is applied to an output of an echo canceler that has processed the received signal. The suppression gain includes a region of sloping attenuation about a decision point. The echo canceler optionally estimates an echo path and subtracts then estimate from the received signal. The suppression gain includes a non-zero lower bound, gmin, on a maximum attenuation applied by a suppressor, that is based on operating conditions of the echo canceler. The region of sloping attenuation applies a variable amount of attenuation that depends on the size of an output error {overscore (e)}(n) of the echo canceler relative to the received signal, x(n).

Abstract: A system and method of digitally modeling and significantly reducing the direct coupling between a telephone appliance loudspeaker and microphone employs a handset microphone in a phone appliance, such as, for example, a speakerphone, as a reference channel along with the speakerphone microphone to reduce the direct coupling between the speakerphone loudspeaker and the speakerphone microphone. Using an analog adaptive echo cancellation scheme, the sensitivity and dynamic range of a telephone device microphone to speech from talkers in an enclosure but not from signals emitted by a telephone loudspeaker are enhanced. Nonlinear distortions produced by a telephone appliance loudspeaker are measured by a telephone appliance handset microphone and used in a feedback subsystem, e.g., network, to reduce nonlinear distortions in the telephone appliance loudspeaker and loudspeaker driving circuit.

Abstract: A communication device includes a speaker, a microphone, and a processor connected to the speaker and the microphone. The processor is arranged for calculating ambient temperature by playing a test sound on the speaker, measuring a transit time of the test sound from the speaker to the microphone, and determining the ambient temperature from the measured transit time. A method of calculating ambient temperature by using a communications device having a speaker, a microphone and a processor is also disclosed. The method can be used for monitoring ambient temperatures of machinery and for detecting fire conditions.

Abstract: The present invention is a desktop speakerphone having a base-station and a detachable microphone pod. The base-station includes standard telephone components, as well as a wireless receiver and a housing for a detachable microphone pod. The detachable pod contains at least one microphone and a wireless transmitter. When the pod is attached to the base-station, and the conference mode of operation is activated, the pod microphone's audio signal goes directly to base-station audio circuitry via a wired connection. When the pod is detached and the conference mode activated, the pod microphone's audio signal now goes via the pod's wireless transmitter to the base-station's wireless receiver. This detached, wireless mode allows the microphone to be positioned anywhere in the room, thereby improving the quality of transmitted speech by increasing the speech-signal-to-room-noise ratio, and lessening the potential for room echo by reducing the acoustic coupling between base-station loudspeaker and pod microphone.