Abstract: A method and apparatus for controlling the transmit volume level of a speakerphone includes receiving a transmit audio signal. If the speakerphone is in a speakerphone mode, the method further includes measuring a send output level of the transmit audio signal, comparing the send output level of the transmit audio signal with a send output level threshold value, and controlling the send output level of the transmit audio signal based upon the comparison of the send output level of the transmit audio signal and the send output level threshold value using automatic gain control. Some embodiments further include determining the send output level threshold value based upon a send loudness rating (SLR) target difference value between a speakerphone SLR target value and a handset SLR target value. In some embodiments, if the speakerphone is in a handset mode, the send output level of the transmit audio signal remains substantially the same.

Abstract: A remote switching for handset handsfree speakerphone operation in a telephone system including an “off of shelf” analog half duplex switching speakerphone IC on a base unit and routs handset handsfree signals via a RF link to and from a microphone and a speakerphone of at least one cordless handset. The remote switching provides a handset handsfree feature on any analog and digital platform that is not equipped with DSPs or other digital means for embedded speakerphone algorithms.

Abstract: A method and apparatus for controlling the transmit volume level of a speakerphone includes receiving a transmit audio signal. If the speakerphone is in a speakerphone mode, the method further includes measuring a send output level of the transmit audio signal, comparing the send output level of the transmit audio signal with a send output level threshold value, and controlling the send output level of the transmit audio signal based upon the comparison of the send output level of the transmit audio signal and the send output level threshold value using automatic gain control. Some embodiments further include determining the send output level threshold value based upon a send loudness rating (SLR) target difference value between a speakerphone SLR target value and a handset SLR target value. In some embodiments, if the speakerphone is in a handset mode, the send output level of the transmit audio signal remains substantially the same.

Abstract: A new speakerphone wherein a loudspeaker is oriented to face the listeners of an audio conference. New speakerphones which have a bass loudspeaker and at least one tweeter loudspeaker wherein the tweeter loudspeaker is oriented towards listeners of an audio conference are also disclosed.

Abstract: Embodiments include a system and method for adapting a wireless device, such as a Bluetooth-enabled mobile handset or other Bluetooth-enabled device to a car radio and associated speaker system to effect a hands-free car kit or similar system. The adapter module is physically and electrically coupled to the car radio by making electrical contact with a connector on the car radio with a matching connector on one side of the adapter module. The mated connectors provide communications from the adapter module to the car radio. The adapter module includes circuitry for communicating with the Bluetooth-enabled mobile handset and the car radio in order to exchange communications signals between the Bluetooth-enabled mobile handset, and a microphone and the car radio.

Abstract: A radio communication system having a plurality of mobile stations, at least one base station, and a control side apparatus connected to the base station. Each mobile station has a mode switching instruction reception unit for receiving an instruction for switching from a radio communication mode for performing a radio communication operation to a loudspeaker mode or a hot mic mode, a destination identifying information storage unit for storing information for identifying a communication apparatus which serves as a communication partner when the mode switching instruction reception unit receives the instruction for switching to the hot mic mode, and a destination identifying information transmission unit responsive to the received instruction for switching to the hot mic mode by the mode switching instruction reception unit for transmitting the information stored in the destination identifying information storage unit over the air.

Abstract: An electronic pillow including a pillow unit encasing at least one error microphone and at least one loudspeaker in electrical connection with a controller unit, the pillow unit also including a power source, and a reference sensing unit including at least one reference microphone in electrical connection with the controller unit, the controller unit including an algorithm for controlling interactions between the error microphone, loudspeaker, and reference microphone. A method of abating unwanted noise, by detecting an unwanted noise with a reference microphone, analyzing the unwanted noise, producing an anti-noise corresponding to the unwanted noise in a pillow, and abating the unwanted noise. Methods of hands-free communication, recording and monitoring sleep disorders, providing real-time response to emergencies, and playing audio sounds.

Abstract: A speakerphone with a jack or a plug to allow a full featured speakerphone to be used with a wireless telephone handset. In one embodiment, a jack is installed on a speakerphone. A cable can connect the speakerphone using this jack and a headset jack on wireless phone handset. In another embodiment, the cable is embedded in the speakerphone. In another embodiment, the speakerphone is operated by an internal power source.

Abstract: A two-way communication apparatus used for two-way speech. In the two-way communication apparatus, a plurality of microphones radially arranged in a horizontal direction are located at equal distances from a receiving and reproduction speaker. The plurality of microphones are located in pairs from the center of the receiving and reproduction speaker. Surface of a sound reflection plate facing the side surfaces of a speaker housing are curved to a flared shape and diffuse the sound output from an upper sound output opening in all orientations in the horizontal direction by cooperating with the sound reflection surface. A DSP receives as input sound pickup signals of one pair of the microphones, selects the microphone for which the highest sound is detected, and transmits the sound pickup signal to the two-way communication apparatus of the other party via a telephone line.

Abstract: An intelligent automatic volume control technique (100) for a communication device is provided that takes a measurement of the background audio environment at the time a user manually selects the volume (102, 104). A user preference is established for the volume setting relative to the background audio level being experienced (106). The informational relationship is stored and used for automatic volume control (108). When the background noise changes (110), the automatic volume control makes an intelligent decision on changing the volume (116). The current background noise level, the initial user volume setting and the background noise level when that volume was set are all used in the volume change decision making process.

Abstract: A telephone headset system having a network interface device, a head set including a headphone and a microphone, and a foot operated, hands free call answering and call ending element. The network interface device, headset, and call answering and call ending element are electronically in communication with each other.

Abstract: The present invention provides an interface between a portable communications device such as a cellular phone and the windshield display of an automobile, enabling textual or graphical data, delivered to the portable communications device to be displayed on the windshield. The interface also enables essential functions of the portable communications device to be integrated into the controls on the steering wheel.

Abstract: A mobile telecommunications system has a handset and a headset for connection to the handset. The handset includes an RF transceiver for transmitting an outgoing call and receiving an incoming call, and a processor coupled to the RF transceiver that provides audio signals on a first audio path to an audio transducer in the handset and on a second audio path for an audio transducer in the headsets. The headset and handset include respective button switches arranged that the operation has the effect both of initiating and/or accepting a call, and of routing audio signals to the respective first or second audio paths. Embodiments are described including a separate switch for toggling the audio paths, and automatic sensors for detecting use of the headset or handset.

Abstract: A telephone system comprising an analog telephone and a full-duplex speakerphone adapter is disclosed. The analog telephone comprises an ordinary analog telephone subscriber circuit for transmitting and receiving analog signals and a handset for users. The full-duplex speakerphone adapter is coupled between the analog telephone and a central office, uses a subscriber loop interface circuit through the first telephone line to couple to the ordinary analog telephone subscriber circuit of the analog telephone and uses a telephone hybrid interface circuit through the second telephone line to couple to a wall jack to communicate with the central office.

Abstract: A small-footprint hands-free speakerphone apparatus includes a loudspeaker, at least one main microphone, at least one reference microphone, and openings for receiving sound. The loudspeaker is disposed within a speaker chamber. Each microphone is mounted in a microphone boot formed by an acoustic opaque resilient material. Each main microphone may be omni-directional or directional. Each reference microphone is omni-directional. An opening is formed in front of each microphone for receiving sound for the microphone. An opening is formed in back of each directional main microphone for receiving sound and forming directivity for the microphone. An opening is formed in the microphone boot for each reference microphone to receive sound from the loudspeaker. An opening may also be formed in the loudspeaker chamber for passing sound to the reference microphone. The apparatus may include one or more interface units to provide interface to external devices.

Abstract: A hands-free device (1) for use with communications devices (3) is provided. In response to operation of a particular user input, the hands-free device (1) causes the communications device (3) with which it is associated to call a particular number. Therefore a call to a particular number can be activated directly by a user via the hands-free device (1). The user input may comprise a dedicated or an existing button on the hands-free device (1). The button may be activated by a pre-determined operation such as a single activation of the button or by a sequence of activations. The particular number to be called may comprise an incoming number that has been stored in a memory of the hands-free device (1).

Abstract: A telematics device (10) for an automotive vehicle has an interface capability with a TDD (36) to provide abilities to transmit and receive TDD data only calls, Voice Carry Over calls and Hearing Carry Over calls.

Abstract: Disclosed are methods and devices for remote determination, control and/or inhibiting the use of a speakerphone of a far end communication device. The methods and devices provide the ability to determine speakerphone use and provide remote control of a far end device's speakerphone, including prompting whether to disable the speakerphone of the far end device if determined to be active. Additionally disclosed are methods and devices of a first communication device having a speakerphone including engaging in a communication with a second communication device, determining if the speakerphone of the first communication device is active, and broadcasting that the speakerphone of the first communication device is active. Also disclosed are methods and devices a first communication device including determining an identity of an auditor at a second communication device and indicating at the first communication device the identity of an auditor at the second communication device.

Abstract: A method of manufacturing a telephony earpiece is provided. The method includes providing a speaker diaphragm and constraining the speaker diaphragm using a cap to provide a thin cavity between the cap and the diaphragm. The first resonance peak of the diaphragm/cavity system is damped by a first slow leak in the cap. The frequency response is built up using a rear resonator in the cap and the high frequency end response is enhanced using a front resonator on an opposite side of said diaphragm as said cap. Positioning of these resonator holes is an important factor. The earpiece is tuned using a second leak to adjust amplitude of low frequency end response.

Abstract: The invention pertains to mobile telephones and can be used during telephone conversations while, for example, operating a mode of transportation. The universal hands-free unit for mobile telephones contains the main module containing a speaker and control electronics, a holder for the mobile telephone, a microphone, an attachment module, and a changeable connection module for electrical connection of the control electronics with the electrical circuits of the mobile telephone. The holder of the mobile telephone is constructed in the form of two plates oriented parallel to each other at a distance L which may be changed by moving at least one plate relative to the other plate with the help of a mechanism located in the body of the main module. A fixating bracket attached to each holding plate, each fixating bracket is made in the shape of a base with several parallel resilient fins.

Abstract: A multi-mode power supply device of a wireless earphone is disclosed. The earphone is communicable bi-directionally with portable communication devices wirelessly through an antenna. The earphone has a battery set. In at least one side of the earphone; an internal of the earphone has a power management circuit. The battery set supplies power to the power management circuit. The power management circuit is used to control the power on or off. The communication devices are selected from portable mobile phones and vehicle used phones. A suspender is capable of being inserted into or buckled into the groove of the earphone so that the suspender is positioned at one side of the power supply module. The suspender has a power supply module. When the suspender is combined to the earphone. The power management circuit is electrically connected to the power supply module.

Abstract: A communications device having a user configurable speakerphone feature is provided. A user may be provided with a plurality of selectable settings for configuring the operation of a microphone or the processing of speech. For example, a user may select settings to filter ambient noise for a cleaner sound or increase a microphone's sensitivity in a conference call environment. In one embodiment, the user may select a setting that changes a microphone level or microphone operating range. When the microphone detects speech, the speech may be processed in accordance with user selected processing settings. For example, a user may select settings to specify a gain control, a frequency response, or an activity threshold. Thus, a user may configure a speakerphone to improve sound quality on the receiving end.

Abstract: The present invention is a Bluetooth™ hands-free kit structure. After the hands-free module according to the present invention executes Bluetooth™ functional pairing with a Bluetooth™-equipped mobile phone, it can be used as a acoustic type hands-free muting system device of Bluetooth™-equipped mobile phone which employs acoustic speakers as its audio output, or can be used as a Bluetooth™-equipped hands-free kit which employs a loudspeaker as its audio output, and also can be used as a Bluetooth™ earphone by itself. The Bluetooth™ hands-free kit structure can be expanded to have both charging and Bluetooth™-functions, and also can be a module structure with private communication switch capability.

Abstract: A microphone, transmitter, speaker, receiver, and power source, all mounted to an eyeglasses frame, for sending and receiving signals wirelessly to and from a remote cell phone or other electronic device. The microphone and the transmitter can be mounted to extension arms that can be extended, pivoted, or otherwise moved to a position for use, and then moved to a stored position when not in use. Alternatively, the microphone, transmitter, speaker, receiver, and power source, can be mounted onto a clip-on or other attachment member that mounts onto a conventional eyeglasses frame, or to a hat or other article worn on the head.

Abstract: A stereo headset (104) with push-to-talk function can be interfaced with a wireless communication device (102) via a connector interface. The connector interface preferably includes a jack at the wireless communication device (102) and a compatible plug at the stereo headset (104). An electrical contact (310) at the connector interface can contemporaneously interconnect both electrical audio signals between the wireless communication device (102) and at least one of the speakers of the stereo headset (104) and electrical user input signals from an external push-to-talk user input device (232) to the wireless communication device (102).

Abstract: Systems and methods are disclosed for packet voice conferencing. An encoding system accepts two sound field signals, representing the same sound field sampled at two spatially-separated points. The relative delay between the two sound field signals is detected over a given time interval. The sound field signals are combined and then encoded as a single audio signal, e.g., by a method suitable for monophonic VoIP. The encoded audio payload and the relative delay are placed in one or more packets and sent to a decoding device via the packet network. The decoding device uses the relative delay to drive a playout splitter—once the encoded audio payload has been decoded, the playout splitter creates multiple presentation channels by inserting the transmitted relative delay in the decoded signal for one (or more) of the presentation channels. The listener thus perceives a speaker's voice as originating from a location related to the speaker's physical position at the other end of the conference.

Abstract: A portable device including a housing and an electro-acoustic transducer. The housing has a first surface with an outlet for the egress of an acoustic signal when in a loudspeaker mode and a second surface with an outlet for the egress of an acoustic signal when in an earpiece mode. The electro-acoustic transducer is located within the housing and converts an electrical signal input to the transducer into an acoustic signal. The transducer is operable to output acoustic signals when in the loudspeaker mode or the earpiece mode, the audio path between the transducer and the outlet for the egress of an acoustic signal when in the loudspeaker mode being less attenuated than the audio path between the transducer and the outlet for the egress of an acoustic signal when in the earpiece mode.

Abstract: A microphone, transmitter, speaker, receiver, and power source, all mounted to an eyeglasses frame, for sending and receiving signals wirelessly to and from a remote cell phone or other electronic device. The microphone and the transmitter can be mounted to extension arms that can be extended, pivoted, or otherwise moved to a position for use, and then moved to a stored position when not in use. Alternatively, the microphone, transmitter, speaker, receiver, and power source, can be mounted onto a clip-on or other attachment member that mounts onto a conventional eyeglasses frame, or to a hat or other article worn on the head.

Abstract: A vehicle communication and control system is provided that may be more readily installed in a vehicle and that utilizes minimal additional wiring. According to some of the disclosed embodiments, the electrical components of the “brick” of a communication and control system are integrated into a rearview mirror assembly. Preferably, the microwave antenna for the GPS and the cellular telephone antenna are also integrated into the rearview mirror assembly. Various functions and features of the system are also disclosed.

Abstract: Systems and methods are disclosed for packet voice conferencing. An encoding system accepts two sound field signals, representing the same sound field sampled at two spatially-separated points. The relative delay between the two sound field signals is detected over a given time interval. The sound field signals are combined and then encoded as a single audio signal, e.g., by a method suitable for monophonic VoIP. The encoded audio payload and the relative delay are placed in one or more packets and sent to a decoding device via the packet network. The decoding device uses the relative delay to drive a playout splitter—once the encoded audio payload has been decoded, the playout splitter creates multiple presentation channels by inserting the transmitted relative delay in the decoded signal for one (or more) of the presentation channels. The listener thus perceives a speaker's voice as originating from a location related to the speaker's physical position at the other end of the conference.

Abstract: The present invention provides a portable, pocket sized speakerphone device adaptable for use with a cellular telephone, and a method for making such a device. The device reduces howling, including echoing and feedback, sufficiently to enable use of the device as a telephone speakerphone. To reduce howling, one or more of the following may be utilized: attenuation circuitry; sound insulation means; positioning the loudspeaker and the microphone of the device such that the outlet of the loudspeaker for emitting sound from the loudspeaker faces in the same direction as the outlet of the microphone for receiving sound into the microphone, and such that a line extending between the outlet of the loudspeaker and the outlet of the microphone would form a right angle with a line extending in the direction of the outlet of the loudspeaker and the outlet of the microphone face.

Abstract: A data processing system comprises an audio processing means receiving data within said data processing system for converting the data into an analog signal with a first and a second analog channel components; an audio output means receiving the analog signal and providing a first and second output signal wherein the first output signal is provided for a loudspeaker and the output second signal is provided for a headset. The control of the audio processing means by a control signal providing an audio signal on the first or on the second channel or on both.

Abstract: A soft mute circuit includes a programmable amplifier controlled by a register. Data is stored in the register from an adder that combines the current data in the register with a second number for increasing or decreasing the gain of the amplifier. A summation circuit includes a plurality of inputs coupled by gates to a summation node and the summation node is coupled to an input of the programmable amplifier. The gates are controlled by suitable logic for selecting input signals in any combination. A control loop maintains the gain of the amplifier at a predetermined level.

Abstract: Embodiments include a system and method for adapting a wireless device, such as a Bluetooth-enabled mobile handset or other Bluetooth-enabled device to a car radio and associated speaker system to effect a hands-free car kit or similar system. The adapter module is physically and electrically coupled to the car radio by making electrical contact with a connector on the car radio with a matching connector on one side of the adapter module. The mated connectors provide communications from the adapter module to the car radio. The adapter module includes circuitry for communicating with the Bluetooth-enabled mobile handset and the car radio in order to exchange communications signals between the Bluetooth-enabled mobile handset, and a microphone and the car radio.

Abstract: This invention includes a speakerphone accessory suitable for connection to either a battery charger having a phone in its pocket or to a cellular telephone. The speakerphone module includes a hemispherical upper housing. The upper housing includes a circular dimple aperture and a wave directing cap. The hemispherical shape, aperture and cap all contribute to directing acoustic waved generated by a speaker disposed within the housing radially from the module in all directions. One embodiment of the module includes a second terminal for passing data and power through the module, allowing the module to be coupled serially between devices. The module also includes a bottom housing having a generally hemispherical shape. The bottom housing provides stability to the connection between the module and a peripheral device in that it reduces the mechanical advantage given to forces incident upon the upper housing acting upon the main terminal.

Abstract: A telephony exchanges allows terminating equipment to indicate whether a telephone call is public, where the telephone conversation may be heard by more than one person at a remote end of a call, or private, where a person at the remote end of a call employs, for example, a handset or a headset. A calling party can restrict a called party from holding a call in a public mode if so desired either before or during the call and is provided through their terminating equipment with an up-to-date graphical display, textual display or physical indication of the status of whether the called-party is operating in a public mode. The called party may also be provided through their terminating equipment with an up-to-date graphical display, textual display or physical indication that they should not put a call on speaker, if the calling party has so decided.

Abstract: A speaker-phone that is operable to perform system change detection, double-talk detection and if desired, optimal step-size control. The invention differentiates between system change and double-talk and is operable to these two situations differently. The invention does not rely solely on the energy measurements that are employed by conventional speaker-phones. Highly reliable system change detection is offered when compared to conventional speaker-phones. The direction and the amplitude of the system change is measured with very good detection probability in the invention. For double-talk detection, the invention does not rely on assumptions that the far-end echoes are of lower amplitude that the near-end signal in performing double-talk detection. The invention performs double-talk detection within a large diversity of echo-paths and background noise levels. A designer may tune the speaker-phone system to ensure proper double-talk detection near low levels of the near-end signal.

Abstract: A method of manufacturing a telephony earpiece is provided. The method includes providing a speaker diaphragm and constraining the speaker diaphragm using a cap to provide a thin cavity between the cap and the diaphragm. The first resonance peak of the diaphragm/cavity system is damped by a first slow leak in the cap. The frequency response is built up using a rear resonator in the cap and the high frequency end response is enhanced using a front resonator on an opposite side of said diaphragm as said cap. Positioning of these resonator holes is an important factor. The earpiece is tuned using a second leak to adjust amplitude of low frequency end response.

Abstract: Apparatus and method to transmit a speakerphone active indication signal to another party over a telephone line upon use of a speakerphone feature, and to transmit a speakerphone inactive indication signal upon cessation of the speakerphone feature. A speakerphone indication transmit module provides an audible or data signal relating to the activation or inactivation of a speakerphone feature to a receiving party's telephone system, which either audibly confirms use of the speakerphone at the opposite end, and/or displays a speakerphone active indication, e.g., on an LED or LCD display. The speakerphone indication active and inactive signals can be, e.g., a single tone, a DTMF tone, FSK signaling, or ADSL signaling.

Abstract: An improved hands-free speaker telephone designed to provide high-quality sound in a relatively small instrument, while at the same time avoiding acoustic shock to a user pressing the device too closely to an ear. If a speakerphone is mistaken for an ordinary portable or cellular phone, or simply out of misguided habit, a user may intentionally or inadvertently press the speaker against an ear. This action may subject the ear to an overly-loud audio event if the speaker begins producing sound, as hands-free speakerphone speakers are typically set to a much higher volume than those of ordinary phones. The effect, which is sometimes referred to as ‘acoustic shock’, is worsened significantly where the user actually succeeds in sealing the phone around the ear, as commonly (and harmlessly) occurs with standard (personal) phones. To avoid this undesirable phenomenon, the hands-free speakerphone is provided with a seal-proof speaker configuration.

Abstract: A multi-directional hand-free kit. The kit has a main body receiving a printed circuit board therein for controlling audio signal sending and receiving incorporated with a mobile communication device and formed with a first oblique portion, a connector member connected to an external power source and formed at a portion thereof facing the first oblique portion with a second oblique portion which frictionally makes contact with the first oblique portion, and a shaft member for connecting the main body and the connector member in such a manner that the main body and the connector member are obliquely rotatable to each other.

Abstract: A video conference system is provided having a base assembly and a loudspeaker assembly in communication with the base assembly by means of a rotable connector is provided. The rotatable connector has an array of springy contacts which are engageable with a compatible array of slide rings, which allows the loudspeaker assembly to be enabling the manually rotated independently of the base assembly, without the loss of electrical contact between the base assembly and the loudspeaker assembly.

Abstract: A portable telephone with a speakerphone with a safety mechanism. This portable telephone is prevented from entering speakerphone mode unless the device is within a predetermined amount of horizontal. Otherwise, speakerphone mode cannot be entered.

Abstract: A modem configurable to operate in a normal mode to perform data communications on the Public Switched Telephone Network (PSTN) additionally configurable to operate in a duplex speakerphone mode. Preferably, the modem is a Personal Computer Memory Card Industry Association (PCMCIA) card for insertion into a connector in a portable computer. The computer includes a sound system with associated microphone and speaker that is incorporated in or associated with the portable computer as the audio input and output for the speakerphone operation. The modem incorporates an interface which allows digitized audio samples from the coder portion of a voice coder-decoder (CODEC) on the modem to be communicated to the computer and digitized audio samples from the computer's sound system to be communicated to the decoder portion of the modem's CODEC. The interface is configured in a manner which is transparent to the modem's normal data communications functions, i.e.

Abstract: A wireless user terminal operates in a mode that is selected based on an indication of the orientation of the wireless user terminal from a gravitational sensor in the wireless user terminal. When the wireless user terminal is in a first orientation, the wireless user terminal operates in a speakerphone mode. When the wireless user terminal is in a second orientation, the wireless user terminal operates in a handset mode. The mode of operation of the wireless user terminal transitions based on movement of the wireless user terminal from the first orientation to the second orientation. For example, when the wireless user terminal placed in a horizontal orientation, one of the speakerphone modes is selected. When the user picks up the wireless user terminal, the wireless user terminal transitions to handset mode.

Abstract: An adaptor for supporting and connecting a portable electronic device, such as a portable phone, computer or other wireless communication device. The adaptor includes a pocket member and an interface module. The portable phone mechanically and electrically connects to the pocket member, and the pocket member mechanically and electrically connects to the interface module. The mechanical and electrical connections between the pocket member and the interface module are common between any interface module and any pocket member. In contrast, the receiving section of the pocket member is varied between different pocket members to accommodate portable electronic devices having different physical constructions. The pocket member attaches to the interface module with a limited, one-dimensional movement of the pocket member relative to the interface module to optimize use of space, particularly in vehicles.

Abstract: A hand-free operator can be externally dialed via a dialing device. It is more particularly related to an external dialing device, which can be applied to all kinds of cellular phones. Thereby people do not have to keep telephone numbers in memory, they can make direct dials on a hand-free operator by means of telephone numbers stored in advance in a memory unit of a dialing device. It mainly houses a hand-free operator circuit and a dial processing unit in a hand-free operator embodiment that operate in collaboration with a signal cable and a dialing device (DTMF acoustic generator). It enables people to make a dial on cellular phones of all kinds via a hand-free operator without memorizing phone numbers or resorting to phone books, effectively facilitating the use of cellular phones and advancing driving safety.

Abstract: A hands-free device and method are provided for implementing a hands-free function to a radio terminal. The hands-free device includes an amplifier for amplifying voice signals received from a microphone; a switching unit for switching the amplified voice signals to a speaker or to an earphone terminal; a controller for controlling the amplifier to amplify the voice signals received from the microphone by a predetermined value and for controlling the switching unit to output the amplified voice signals via the earphone terminal if the controller determines that the hands-free function has been selected; and an external voice output unit having an input terminal connected to the earphone terminal for receiving the amplified voice signals and a voice output speaker for outputting the amplified voice signals.