Abstract: Systems and methods for variably and/or shiftably limiting signal output are disclosed. The system may include an attenuation circuit having an attenuation network activated by a source signal crossing a threshold to attenuate the source signal and a resistive element such as resistors bridging between the attenuation circuit input and output for variably attenuating the source signal. The attenuation circuit may be activated by a switch such as transistors. To shift the limiting threshold, the system may include a circuit to shift the activating threshold, the circuit having a control voltage source such as DC voltage source coupled to the attenuation network. The threshold shifting circuit may be configured to selectively increase the threshold during music listening and to be inactive during voice applications. The system may be incorporated in a headset adapter or a headset receiver.

Abstract: A system and method detects whether or not a microphone apparatus is positioned incorrectly relative to an acoustic source and of automatically compensating for such mispositioning. A position estimation circuit determines whether the microphone apparatus is mispositioned. A controller facilitates the automatic compensation of the mispositioning.

Abstract: Improper microphone position and speech level on a telephone headset is sensed by comparison of a speech envelope to multiple signal threshold levels. A first threshold is used to determine whether a headset user is talking. A second threshold is used to determine whether a signal level at the microphone is sufficiently strong for proper communication. An indicator is activated when the user is talking and the signal level is too weak. Typically, a weak signal is caused by a mispositioned microphone or a user talking too softly.

Abstract: A system and method detects whether or not a microphone apparatus is positioned incorrectly relative to an acoustic source and of automatically compensating for such mispositioning. A position estimation circuit determines whether the microphone apparatus is mispositioned. A controller facilitates the automatic compensation of the mispositioning.

Abstract: An acoustic signal level limiter provides a telephone handset/headset user protection against loud audible signals generated within a communications system. The acoustic signal limiter comprises an acoustic signal level attenuation circuit and at least one acoustic signal level relay circuit. Once activated, the acoustic signal level attenuation circuit creates an attenuation network that attenuates an electrical acoustic signal transmitted through the communications system. Acoustic signal level relay circuits are activated to further attenuate the electrical acoustical signal to prevent the acoustic signal level attenuation circuit from operating in a deep saturation mode and provide further hearing safety for the telephone headset/handset user. A fuse in series and “Zener Zap” shunting transistor diodes provide assured higher signal level protection.

Abstract: Improper microphone position and speech level on a telephone headset is sensed by comparison of a speech envelope to multiple signal threshold levels. A first threshold is used to determine whether a headset user is talking. A second threshold is used to determine whether a signal level at the microphone is sufficiently strong for proper communication. An indicator is activated when the user is talking and the signal level is too weak. Typically, a weak signal is caused by a mispositioned microphone or a user talking too softly.

Abstract: Improper microphone position and speech level on a telephone headset is sensed by comparison of a speech envelope to multiple signal threshold levels. A first threshold is used to determine whether a headset user is talking. A second threshold is used to determine whether a signal level at the microphone is sufficiently strong for proper communication. An indicator is activated when the user is talking and the signal level is too weak. Typically, a weak signal is caused by a mispositioned microphone or a user talking too softly.

Abstract: A method and apparatus for monitoring and controlling exposure to noise related to a headset are described. The method includes sampling an input sound signal to produce samples of the input sound signal, calculating from these samples a headset sound level corresponding to the input sound signal, calculating cumulative exposure of a headset user to the headset sound level at a specific point in time, and calculating a gain adjustment for the input sound signal to ensure that the total sound to which the headset user will be exposed during a selected time period is within the regulatory maximum level. Advantageously, the method and apparatus of the present invention allow accurate real-time monitoring of cumulative exposure to headset noise and real-time adjustment of headset gain to ensure compliance with regulatory maximum sound exposure levels.

Abstract: A headset storage device includes a headset cradle, a switch and a manual override device. The headset cradle has two positions: a first position when the headset cradle is supporting a headset and a second position when the headset cradle is not supporting a headset. The switch couples the audio signal to the alternate audio system when the headset cradle is in the first position and to the headset when the headset cradle is in the second position. The manual override device forces the headset cradle into one of the two positions regardless of whether the headset cradle is supporting a headset.

Abstract: A telephone headset adapter includes a deck with a top surface for supporting a telephone. The deck is placed underneath a telephone, and the weight of the telephone is applied on the deck and stabilizes the deck. The deck includes a primary or fixed deck portion and a movable deck portion. The movable deck portion is coupled to the fixed deck portion by an extension slide. The movable deck portion is movable along the extension slide to vary the width of the deck. Thus, the deck can support and accommodate telephone sets of various sizes and configurations. Routing channels are also formed within the top surface of the deck for receiving cords that are used with the telephone set, handset, headset and accessories, thereby minimizing cord tangling and clutter. An electronic housing is removably coupled to an end of the deck. The electronic housing contains adapter components for coupling the telephone to the headset or handset.

Abstract: A method and apparatus for monitoring and controlling exposure to noise related to a headset are described. The method includes sampling an input sound signal to produce samples of the input sound signal, calculating from these samples a headset sound level corresponding to the input sound signal, calculating cumulative exposure of a headset user to the headset sound level at a specific point in time, and calculating a gain adjustment for the input sound signal to ensure that the total sound to which the headset user will be exposed during a selected time period is within the regulatory maximum level. Advantageously, the method and apparatus of the present invention allow accurate real-time monitoring of cumulative exposure to headset noise and real-time adjustment of headset gain to ensure compliance with regulatory maximum sound exposure levels.

Abstract: A hookswitch actuator including an activating mechanism which maintains the hookswitch circuit of a telephone in an "on hook" state when the activating mechanism is in a first position, or in an "off hook" state when the activating mechanism is in the second position. The movement of the activating mechanism between the two positions is accomplished through the use of a shape memory alloy mechanism. The shape memory alloy mechanism is coupled to the activating mechanism in such a way that heating or cooling of the shape memory alloy mechanism moves the activating mechanism between its two positions. Control of the heating and cooling of the shape memory alloy mechanism is effectuated by controlling the amount of electric current passing through it.

Abstract: A communications headset includes a headset enclosure and a receiver enclosure coupled thereto by various means allowing displacement of the receiver enclosure with respect to the headset enclosure at any of a variety of angles, rotations, and distances. The adaptable positioning of the receiver enclosure allows the headset to be used by a wide variety of users having different ear shapes and sizes, while providing a stable, comfortable fit and ensuring good acoustic performance. In one embodiment the receiver enclosure is slidably coupled to a ball tube having a ball that rests in a socket of the headset enclosure. The receiver enclosure can telescope along the length of the ball tube and can rotate about an axis of the tube. The ball can be rotated in the socket to position the receiver enclosure at any of a variety of angles relative to the headset enclosure. A voice transmitter is also coupled to the headset enclosure so as to allow adjustment of length, angular position, and rotation.

Abstract: An electronic telephone set for use with a telephone headset receiver/transmitter apparatus is disclosed. The telephone set is line-powered, and is capable of transmit muting, last number re-dial, and memory dialing. The volume of the received voice signal is controllable by a user, and a visual indication of the volume setting is provided. The receiver and transmitter amplifiers includes circuitry for compensating for the frequency response characteristics of two or more headsets, the compensation circuitry being selectively and automatically engaged by means of a programmable connecting jack. The design of the telephone is such that it consumes very little power, especially during "on-hook" operation. Moreover, an electrical storage device is employed to provide continuous operational power to the dialer circuitry and electronic hook-switch control circuitry, so that the telephone set retains its dialing memory when not in use.

Abstract: A telephone set adapted for use by hearing impaired and visually impaired persons is disclosed in which the frequency response of audio signals produced from the handset receiver of the telephone is shaped to have enhanced high-frequency characteristics. The telephone is further provided with indicator lights which flash in conjunction with the telephone's electronic ringer to indicate an incoming telephone call. An array of light-emitting diodes is disposed beneath a dialer keypad to facilitate viewing of the dialing buttons in darkened environments. The dialer keypad's buttons are of an enlarged size, so that they may be more easily used by persons with impaired vison or motor skills.

Abstract: A lightweight, monaural communications headset is disclosed which is readily adjustable to be worn on either the right or left ear of a wearer. The disclosed headset consists of two housings, one for holding electronic circuitry for the headset, and the other for holding an acoustical transmitter. The two housings are coupled with a swivel or ball-and-socket coupling, so that the device may be positioned behind either the right or left ear of a wearer. The transmitter housing is provided with acoustical port holes on both of its sides to further facilitate the reversible wearing of the device. The disclosed headset is constructed from lightweight materials so that it is self-supporting, and causes minimal discomfort to the wearer.