Abstract: It is an object of the invention to provide a headset for performing simultaneous two-way communication or alternate two-way communication, which has excellent sound insulating properties such that external noise is not possibly mixed even when used under high noise conditions. A pair of bowl-shaped housings 1 each having an annular pad 2 attached to the rim of an opening portion are connected together through a headband 3, an acoustic speaker 5 supported by a buffer material 4 is arranged in at least one of the housings 1, and a bone conduction microphone 6 supported by the buffer material 4 such that the distal end is brought into abutment against the ear or the portion around the ear when a user wears the headset is arranged in at least one of the housings 1.

Abstract: It is an object of the invention to provide a headset for performing simultaneous two-way communication or alternate two-way communication, which has excellent sound insulating properties such that external noise is not possibly mixed even when used under high noise conditions. A pair of bowl-shaped housings 1 each having an annular pad 2 attached to the rim of an opening portion are connected together through a headband 3, an acoustic speaker 5 supported by a buffer material 4 is arranged in at least one of the housings 1, and a bone conduction microphone 6 supported by the buffer material 4 such that the distal end is brought into abutment against the ear or the portion around the ear when a user wears the headset is arranged in at least one of the housings 1.

Abstract: An object of the invention is to provide a voice input/output automatic switching circuit used in a hand-held microphone with speaker of a communication device such as a transceiver. In the voice input/output automatic switching circuit, a circuit for detecting a handsfree speaker/microphone can be simply configured without requiring a particular detection terminal and moreover, a sufficient countermeasure can be taken against a malfunction caused upon its switching.

Abstract: A transceiver, which is capable of being used even in a severe situation such as situations in salvage operations and the like in which the transceiver is often submerged, is composed of: a PTT switch for transmitting an audio signal upon depression of the switch; a sound input/output portion for inputting and outputting a sound; and a main body portion for transmission and reception of a radio signal. All of the above components except the main body portion are formed into independent and connecting cables are provided between the independent units and the main body.

Abstract: To provide a hearing aid that allows desired sound to be selectively heard and allows unnecessary sound not to be heard, and that can be used with no bars even in a situation like a meeting that requires a conversation with a plurality of persons. The hearing aid includes: a hearing aid body having a hearing aid function and an external microphone signal receiving function; and a separate external microphone, wherein connection and disconnection of communication between the above described hearing aid body and the external microphone are automatically switched, and the above described hearing aid body functions as a normal hearing aid when the communication between the above described hearing aid body and the external microphone is disconnected.

Abstract: Transmission of an audio signal is performed alternately in a first and a second condition in precisely timed sequence. In the first condition, the audio signal is inverted in frequency spectrum. In the second condition, the audio signal is normal. Due to this, a cryptographic apparatus is improved in security in communication. in a radio communication system linked to a radio network for transmitting an audio signal having been inverted in frequency spectrum to render the signal unintelligible, there are provided: a transmitter-side frequency spectrum inversion/non-inversion circuit including a frequency spectrum inversion circuit; a CPU for generating a control signal; a transmitter-side frequency spectrum inversion/non-inversion change-over switch; and, a sub-carrier oscillator. The CPU controls both the frequency spectrum inversion/non-inversion switch and the sub-carrier transmitter.

Abstract: A transceiver, which is capable of being used even in a severe situation such as situations in salvage operations and the like in which the transceiver is often submerged, comprises: a PTT switch for transmitting an audio signal upon depression of the switch; a sound input/output portion for inputting and outputting a sound; a main body portion for transmission and reception of a radio signal; wherein all the above components except the main body portion are formed into independent units; wherein means for transmitting and receiving a signal between the independent units and the main body portion is provided.

Abstract: The present invention relates to a frequency translation transceiver of a communication means employed in a limited group of members, the number of which is, for example, approximately 10 persons, wherein the transceiver is free from any illegal tapping and interference and characterized by comprising: a memory unit for storing and setting a plurality of frequencies and its own identification number; a receiver circuit for performing a scanning operation of the plurality of frequencies in its receiving mode to obtain an incoming signal; a detection circuit for extracting data of an identification number of the incoming signal having been received by the receiver circuit; and, a transmitter circuit for transmitting data of the own identification number together with an audio signal.

Abstract: To provide a hearing aid that allows desired sound to be selectively heard and allows unnecessary sound not to be heard, and that can be used with no bars even in a situation like a meeting that requires a conversation with a plurality of persons. The hearing aid includes: a hearing aid body having a hearing aid function and an external microphone signal receiving function; and a separate external microphone, wherein connection and disconnection of communication between the above described hearing aid body and the external microphone are automatically switched, and the above described hearing aid body functions as a normal hearing aid when the communication between the above described hearing aid body and the external microphone is disconnected.

Abstract: In the apparatus, in accordance with the presence or absence of a barrier, arrangement of its light-receiving and its light-emitting element is changed to avoid interference with its proper light-receiving operation from the barrier, which makesso the apparatus free from noise problems, malfunctions and like troubles caused by the interference. In construction, a cover 2 permeable to infrared is rotatably mounted on a base 1. A stationary base plate 9 and a movable base plate 10, which is rotatable together with the cover 2, are stacked together inside the cover 2 to realize a two-layer arrangement. Each of these base plates 9, 10 carries a light-receiving element 7, 12 and/or a light-emitting element 8, 13, and assumes a substantially semicircular shape.

Abstract: In the method and apparatus, a light receiving element 1 is prevented from being exposed to the direct light of the sun so that a signal is transmitted by means of infrared rays in a favorable and steady manner. a transmitter 4 carried by a driver emits the infrared rays 6, 7 toward a floor surface of the vehicle. The light receiving element 1 is oppositely disposed from such floor surface to receive a reflected component of the infrared rays 6, 7. The apparatus comprises: the transmitter 4, which is carried by the driver and provided with a light emitting element 5 for emitting the infrared rays 6, 7 toward the floor surface; and, a receiver 3 installed in a front panel of the vehicle, in which receiver 3 the light receiving element 1 is mounted.