as) United States
`a2) Patent Application Publication (10) Pub. No.: US 2003/0223604 Al
`(43) Pub. Date: Dec.4, 2003
`
`Nakagawa
`
`US 20030223604A1
`
`(54) AUDIO OUTPUT APPARATUS HAVING A
`WIRELESS COMMUNICATION FUNCTION,
`AND METHOD OF CONTROLLING
`SOUND-SOURCE SWITCHING IN THE
`APPARATUS
`
`Publication Classification
`
`(SL) Ute C07 cacsccsssssssssssnssessesnstsntsnstsevee HO4R 5/02
`(52) US. Ch.
`cecescsssssssscnstssssetnsenssstn 381/311; 381/309
`
`(57)
`
`ABSTRACT
`
`(75)
`
`Inventor: Hideyuki Nakagawa, Kunitachi-shi
`An audio output apparatus comprises a sound output unit
`GP)
`configured to output sound that corresponds to the audio
`data transmitted fromafirst sound source device connected
`Correspondence Address:
`by radio to the audio output apparatus, a priority-level
`PILLSBURY WINTHROP, LLP
`comparing unit configured to compare priority information
`P.O. BOX 10500
`transmitted from the first sound source device and repre-
`senting a priority level assigned thereto, with priority infor-
`mation transmitted from a second sound source device and
`
`MCLEAN,VA 22102 (US)
`
`(73) Assignee: KABUSHIKI KAISHA TOSHIBA,
`Tokyo (JP)
`
`(21) Appl. No.:
`
`10/359,194
`
`(22)
`
`Filed:
`
`Feb. 6, 2003
`
`(30)
`
`Foreign Application Priority Data
`
`May 28, 2002
`
`(JP) ..eeeseesssesssssescneeeneeneees 2002-153685
`
`representing a priority level assigned thereto, when the
`second sound source devices is connected by radio to the
`audio output apparatus while the audio output apparatus is
`outputting sound corresponding to the audio data transmit-
`ted from the first sound source device, and a sound-source
`selecting unit configured to select one of the first and second
`sound source devices, as a source of sound to be output, in
`accordance with the result of comparison performed by the
`priority-level comparing unit.
`
`11
`
`
`Wireless audio
`output apparatus
`(Wireless headset)
`
`
`
`1
`
`APPLE 1022
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Sound source device #1
`
`Audio player
`(music)
`
`Priority information
`
`Sound source device #2
`
`Mobile phone
`(speech)
`
`Priority information
`
`
`
`
`
`Sound source device #3
`
`
`
`
`14
`
`Audio guidance device
`(News, guidance)
`
`Priority information
`
`APPLE 1022
`
`1
`
`

`

`>
`
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`
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`d
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`headset)
`apparatus
`audio(J
`
`I\
`
`I
`
`111
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`I
`
`�
`
`11
`
`I I/
`
`141 /
`
`w•
`
`2 •
`
`131 "' 113
`
`'
`
`'
`
`I I"-
`
`12 ----7
`
`Sound source
`
`Priority
`information
`(News,
`guidance)
`14 ----7 Audio guidance
`device
`Sound source
`#3
`device
`Priority
`information
`(Wireless
`output
`I / 7 Wireless
`(speech)
`13� Mobile
`phone
`Sound source
`#2
`device
`Priority
`information
`I �
`(music)
`Audio player
`device
`#1 w
`121
`
`FIG. 1
`
`T'
`
`I
`
`I
`
`I
`
`2
`
`

`

`Patent Application Publication
`
`Dec. 4, 2003 Sheet 2 of 5
`
`US 2003/0223604 Al
`
`12
`
`Sound source device #1
`
`.
`
`Wireless
`communication device
`
`| Base-band
`
`processing unit
`& RF unit
`
`|
`
`requesting unit
`
`System control unit
`
`2
`
`Prior-connection
`
`FIG.2
`
`in
`
`
`
`Wireless audio output apparatus
`
`
`
`& RF unit
`
`
`
`
`
`Prior-connection
`Audio-data
`
`
`request analyzing unit
`generating unit
`
`
`
`
`
`
`Sound-source
`Audio-data
`
`
`switching unit
`outputting unit
`
`
`
`
`Wireless
`communication device
`Base-band
`processing unit
`
`
`
`
`
`FIG.3
`
`3
`
`

`

`Patent Application Publication
`
`Dec. 4, 2003 Sheet 3 of 5
`
`US 2003/0223604 Al
`
`Sound source device
`(Start)
`
`Wireless audio output apparatus
`CStart)
`
` Is it requested
`
`
`
`
`that audio data be output
`to the wireless audio output
`apparatus ?
`
`YES
`$112
`|Establishwirelessconnection|
`
`$113
`|Establishwirelessconnection|
`
`sit ik
`
`request
`
`request
`
`
`
`Any other
`$116
`
`
`
`sound source device
`NO
`
`has been connected to the
`
`
`wireless audio output
`apparatus ?
` YES
`S117
`
`Compare the priority level of
`
`the sound source device that
`has transmitted a prior-
`connection request, with the
`
`priority level of the sound
`
`source device that is
`
`connected to the wireless
`
`audio output apparatus
`
`
`
`
`[Priority
`S118
`
`level of the sound
`
`
`source device that has
`
`
`transmitted the request] > [priority
`
`
`
`
`$119
`level of the sound source
`
`
`
`device that is connected
`necessary to ask the
`
`
`NO
`to the apparatus]
`
`user for sound source
`
`9
`switching permission
`9
`
`YES
`
`NO
`
`4
`
`

`

`Patent Application Publication
`
`Dec. 4, 2003 Sheet 4 of 5
`
`US 2003/0223604 Al
`
`Permission
`received from the
`
`user ?
`
`
`
`
`
`Switch the sound source to the
`device that has transmitted a
`prior-connection request
`
` A disconnection
`
`?
`Transmit a disconnection request
`request received
`to any other device not selected
`at present
`
`
`Disconnect the radio connection
`
`Keep transmitting and receiving audio data
`
`FIG.5
`
`Parameter
`
`Parameter | Parameter
`7 i
`
`‘
`
`N.
`
`\
`
`~
`
`~.
`
`{
`
`\\
`
`1
`\
`t
`
`Priority notifying command|of bytes|information
`
`
`Priority-level
`Number
`
`5
`
`

`

`Patent Application Publication
`
`Dec. 4, 2003 Sheet 5 of 5
`
`US 2003/0223604 Al
`
`Re-selection of a sound source device
`
`Audio data is being transmitted
`
`
`
`
`
`Aae
`
`
`
` Disconnect the wireless connection with the
`
` Any sound
`
`
`
`
`request for the device now
`selected ?
`
`device selected now
`
`source device connected
`and not selected
`9
`
`
`
`} Select the sound source device
`
`FIG. 7
`
` Time
`
`Sound source
`device #1
`
`Sound source
`device #2
`
`Sound source
`device #1
`
`Audio
`output
`
`Prior-connection request
`from sound source device #2
`
`Disconnection request to
`sound source device #2
`
`FIG.8
`
`6
`
`

`

`US 2003/0223604 Al
`
`Dec.4, 2003
`
`AUDIO OUTPUT APPARATUS HAVING A
`WIRELESS COMMUNICATION FUNCTION, AND
`METHOD OF CONTROLLING SOUND-SOURCE
`SWITCHING IN THE APPARATUS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`BRIEF SUMMARY OF THE INVENTION
`
`[0011] Embodiments of the present invention may provide
`an audio output apparatus and a sound-source switching
`method that can automatically switch one sound source
`device to another.
`
`[0012] According to an embodimentof the present inven-
`tion, there is provided an audio output apparatus capable of
`[0001] This application is based upon and claims the
`performing a wireless communication with a sound source
`benefit of priority from the prior Japanese Patent Application
`device that transmits audio data, comprising: a sound output
`No. 2002-153685, filed May 28, 2002, the entire contents of
`unit configured to output sound that correspondsto the audio
`which are incorporated herein by reference.
`data transmitted fromafirst sound source device connected
`BACKGROUND OF THE INVENTION
`
`[0002]
`
`1. Field of the Invention
`
`[0003] The present invention relates to an audio output
`apparatus such as a wireless headphone and to a method of
`controlling sound-source switching in the audio output appa-
`ratus. More particularly, the invention relates to an audio
`output apparatus that can communicate by radio with vari-
`ous types of sound sources such as portable audio players
`and mobile phones, and to a method of controlling sound-
`source switching in the audio output apparatus.
`
`[0004]
`
`2. Description of the Related Art
`
`In recent years, various types of portable audio
`[0005]
`players, such as portable CD (Compact Disk) players and
`portable mini-disk players, have come into common use.
`The users can enjoy listening to music, whereverthey are.
`
`[0006] Usually, the user of a portable audio player wears
`a headphoneto listen to the music the player is reproducing.
`While wearing the headphone, he or she may fail to hear
`guidance madeat railway stations or in trains, and may not
`aware of call arriving at his or her mobile phone.
`
`Jpn. Pat. Appln. KOKAI Publication No. 2001-
`[0007]
`197019 discloses a CD player. When the CD player receives
`a connection request
`from an external communications
`device, the sound source is switched from the music data
`being reproduced from the CD, to the audio data transmitted
`by radio from the external communications device.
`
`[0008] Every time the CD player receives a connection
`request, the CD player stops reproducing the data from the
`CD. Hence, the sound source must be switched from the
`music data to be reproduced from the CD,
`to the data
`transmitted from the external communications device, no
`matter which kind of music data is being reproduced.
`
`[0009] The CD player disclosed in the Publication is
`designed to achieve one-to-one communication with a speci-
`fied external communications device. It is not configured to
`communicate with a plurality of external communications
`device functioning as sound sources that can transmit audio
`data in the form of radio signals.
`
`is expected that various types of electronic
`It
`[0010]
`apparatuses(e.g., portable audio players, mobile telephones
`and the like) that can perform short-range wireless commu-
`nication will be developed and used as sound sourcesin the
`near future, thanks to the short-range communication tech-
`nology represented by Bluetooth™. In view ofthis, the CD
`player must generate sound not only from the music data
`recorded on the CD or the audio data transmitted from an
`external sound source device, but also from a plurality of
`external sound source devices.
`
`by radio to the audio output apparatus; a priority-level
`comparing unit configured to compare priority information
`transmitted from the first sound source device and repre-
`senting a priority level assigned thereto, with priority infor-
`mation transmitted from a second sound source device and
`
`representing a priority level assigned thereto, when the
`second sound source devices is connected by radio to the
`audio output apparatus while the audio output apparatus is
`outputting sound corresponding to the audio data transmit-
`ted from the first sound source device; and a sound-source
`selecting unit configured to select one of the first and second
`sound source devices, as a source of sound to be output by
`the sound output unit,
`in accordance with the result of
`comparison performed bythe priority-level comparing unit.
`
`[0013] Additional features and advantages of the inven-
`tion will be set forth in the description which follows, and
`in part will be obvious from the description, or may be
`learned by practice of the invention. The features and
`advantages of the invention mayberealized and obtained by
`meansof the instrumentalities and combinations particularly
`pointed out hereinafter.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWING
`
`[0014] The accompanying drawings, which are incorpo-
`rated in and constitute a part of the specification, illustrate
`embodiments of the invention, and together with the general
`description given above and the detailed description of the
`embodiments given below,serve to explain the principles of
`the invention.
`
`[0015] FIG. 1 is a diagram showing the relation between
`an audio output apparatus that is an embodiment of the
`invention and the sound source devices that are connected
`by radio to the audio output apparatus;
`
`FIG.2 is a block diagram illustrating the wireless
`[0016]
`audio communication function provided in each of the sound
`source devices shown in FIG. 1;
`
`[0017] FIG. 3 is a block diagram illustrating a structure
`that the audio output apparatus of FIG. 1 may have;
`
`[0018] FIG. 4 is a flowchart explaining a part of the
`procedure of switching one sound source to another in the
`audio output apparatus shown in FIG.1;
`
`[0019] FIG. 5 isa flowchart explaining the remaining part
`of the procedure of switching one sound source to another in
`the audio output apparatus shown in FIG.1;
`
`[0020] FIG. 6 is a diagram depicting a format for the
`priority information that is supplied from a sound source
`
`7
`
`

`

`US 2003/0223604 Al
`
`Dec.4, 2003
`
`device shown in FIG. 1 to the audio output apparatus when
`the sound source device is connected by radio to the audio
`output apparatus;
`
`[0021] FIG. 7 is a flowchart explaining a procedure that
`the audio output apparatus of FIG. 1 may perform to select
`a sound source device again; and
`
`[0022] FIG. 8 is a diagram illustrating how the first and
`second sound source devices are switched from one to the
`
`other when the audio output apparatus performs the proce-
`dure depicted in FIG.7.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`[0023] Embodiments of this invention will be described,
`with reference to the accompanying drawings.
`
`[0024] FIG. 1 showsthe relation between an audio output
`apparatus that is an embodiment of the invention and the
`sound source devices that are connected by radio to the
`audio output apparatus. The audio output apparatus 11 is
`configured to receive audio data transmitted in the form of
`a radio signal from any sound source device and to generate
`sound from the audio data. The sound that the apparatus 11
`generates is output via speaker or a headphone.
`
`[0025] The audio output apparatus 11 is, for example, a
`wireless headset (comprising a speaker and a microphone).
`The user who wears the wireless headset can listen to the
`
`audio data transmitted, by a radio signal, from a sound
`source device and output through the headphone(or ear-
`phone) 111 that
`is provided as speaker in the wireless
`headset.
`
`[0026] The wireless communication between the wireless
`audio output apparatus 11 and anyone of the sound source
`devices is implemented by a short-range communications
`system that accords with the Bluetooth™ standards. The
`wireless audio output apparatus 11 can therefore perform a
`wireless communication with various sound source devices
`having wireless communication function that are based on
`the Bluetooth™ standards.
`
`[0027] Sound source devices are wireless audio transmit-
`ters that can transmit audio data representing speech, music
`and the like, in the form of radio signals. Assumethat three
`sound source devices 12, 13 and 14 of difference types are
`available for the embodimentof the invention.
`
`[0028] The sound source device (#1) 12 is a portable audio
`player such as a portable CD (Compact Disk) player or a
`portable mini-disk player. It has a short-range communica-
`tion function that accords with the Bluetooth™ standards.
`This sound source device 12 has an antenna 121. The device
`
`12 reads music data from a removable recording medium
`such as a CD or a mini-disk. The music data is transmitted
`
`by a radio signal, as audio data, from the antenna 121 to the
`wireless audio output apparatus 11. The user may put the
`sound source device (#1) 12 into a bag he or she hasor into
`a pocket of the jacket he or she wears. Then, the user can
`listen to the music that the headphone 111 of the wireless
`audio output apparatus 11 is reproducing from the music
`data transmitted from the sound source device (#1) 12.
`
`[0029] The sound source device (#2) 13 is a mobile phone.
`It has a wireless communication function based on the
`Bluetooth™standards, in addition to the function of achiev-
`
`ing wireless communication with the mobile phone network.
`This sound source device (#2) 13 has an antenna 131. The
`device 13 receives speech data from a base station incorpo-
`rated in the mobile phone network and transmits the speech
`data, as audio data, from the antenna 131 to the wireless
`audio output apparatus 11. The user may put the sound
`source device (#2) 13 into a bag he or she has or into a
`pocket of the jacket he or she wears. Then, the user can hear
`the call-arrival tone and the speech of the calling person,
`which the headphone 111 of the apparatus 11 is reproducing
`from the audio data transmitted from the sound source
`device (#2) 13.
`
`[0030] The wireless audio output apparatus 11 has a
`microphone 112. The user’s speech input to the microphone
`112 is transmitted by a radio signal from the antenna 113 to
`the sound source device (#2) 13. Thereby, the user can talk
`the calling person through the mobile phone network.
`
`[0031] The sound source device (#3) 14 is, for example, an
`audio guidance device provided at railway stations or in
`trains. It has a wireless communication function that accords
`with the Bluetooth™ standards.
`
`[0032] The sound source device (#3) 14 has an antenna
`141. From the antenna 141, news, guidance or the like is
`transmitted, in the form of audio data, to the wireless audio
`output apparatus 11.
`
`[0033] The wireless audio output apparatus 11 has the
`function of automatically switching any one of the sound
`source devices 12, 13 and 14 to another, as source of sound
`to be output by the apparatus 11. The automatic switching of
`sound source is performed in accordance with priority
`information. The information items representing the differ-
`ent priority levels that are assigned to the sound source
`devices 12, 13 and 14. The sound source device having the
`highest priority is selected as a source of sound to be output
`by the apparatus 11,prior to any other sound source devices.
`
`[0034] When the sound source devices 12, 13 and 14 are
`connected by radio to the wireless audio output apparatus 11,
`they transmit the priority information items to the audio
`output apparatus 11, thus informing the apparatus 11 of the
`priority levels assigned to them. The wireless audio output
`apparatus 11 compares the priority levels of the sound
`source devices that are connected to it and selects the sound
`source device having the highest priority level. Thus, if a
`sound source device is connected by radio to the apparatus
`11 and has a higher priority level than the sound source
`device now selected, the sound source for the apparatus 11
`will be automatically switched to the sound source device
`newly connected to the apparatus 11. The user need not
`perform this switching of sound source. Conversely, if a
`sound source device having a lowerpriority level than the
`sound source device now selected is connected by radio to
`the apparatus 11, the sound source will not be switchedatall.
`In this case, the user can keep listening to, for example, the
`music represented by the audio data transmitted from the
`sound source device selected at present.
`
`[0035] The sound source device (#1) 12, which is a
`portable audio player, is triggered when the user operates it
`to reproduce, for example, music data. Thus triggered, the
`device 12 transmits a wireless-connection request to the
`audio output apparatus 11 and performs the procedure of
`establishing wireless connection (physical wireless link)
`
`8
`
`

`

`US 2003/0223604 Al
`
`Dec.4, 2003
`
`between it and the audio output apparatus 11. When the
`wireless connection is established, the sound source device
`(#1) 12 transmits to the apparatus 11 thepriority information
`item that represents the priority level assigned to it.
`
`[0036] The priority level assigned to the sound source
`device (#1) 12 and represented by the priority information
`item stored in the device (#1) 12 is not fixed. The user can
`changethe priority level to a desired value by operating, for
`example, the interface button switch provided on the sound
`source device (#1) 12.
`
`[0037] The sound source device (#2) 13, which is a mobile
`phone, is triggered whenit receives a call from, for example,
`the mobile telephone network. Thustriggered, the device 13
`transmits a wireless-connection request to the audio output
`apparatus 11 and performs the procedure of establishing
`wireless connection (physical wireless link) between it and
`the audio output apparatus 11. Whenthe wireless connection
`is established, the sound source device (#2) 13 transmits to
`the apparatus 11 the priority information item that represents
`the priority level assigned to it. The priority level assigned
`to the sound source device (#2) 13 and represented by the
`priority information item stored in the device (#2) 13 is not
`fixed, as in the case of the sound source device (#1) 12. The
`user can change the priority level to a desired value by
`operating, for example, the interface button switch provided
`on the sound source device (#2) 13.
`
`[0038] The same person usually uses the wireless audio
`output apparatus 11 and the sound source devices 12 and 13.
`The user can therefore assign any priority levels he or she
`wants to the sound source devices 12 and 13.
`
`[0039] Assumethat the user has assigned a higher priority
`level to the sound source device 13 than to the sound source
`
`device 12. The sound source device 13 may be connected by
`radio to the wireless audio output apparatus 11 while the
`headphone111 of the apparatus 11 is generating sound from
`the audio data transmitted from the sound source device 12.
`In this case, the sound source, from which the wireless audio
`output apparatus 11 (ultimately, the headphone 111) should
`reproduce audio data, is automatically switched from the
`sound source device 12 to the sound source device 13.
`Hence, when the sound source device 13 receives a call
`while the user is listening the music represented by the
`music data transmitted from the sound source device 12, the
`user can hear, without fail, the calling tone and the caller’s
`speech.
`[0040] The sound source device 12 should be discon-
`nected from the wireless audio output apparatus 11 imme-
`diately after the sound source is switched from the sound
`source device 12 to the sound source device 13. Once the
`device 12 is so disconnected from the apparatus 11, it is
`possible to avoid the useless occupation of a wireless
`channel for transferring audio data that the headphone 11
`will not output.
`[0041] Usually, the sound source device 12, which is an
`audio player, keeps reading music data and reproducing the
`same from the recording medium, even after it is discon-
`nected from the wireless audio output apparatus 11. In view
`of this it is desired that sound source device 12 be triggered
`to transmit a wireless-connection request every time it
`finishes reading one music data item from the recording
`medium (for example, from one track provided on the
`recording medium).
`
`[0042] Thus, the sound source device 12 can transmits a
`wireless-connection request to the wireless audio output
`apparatus 11, every timeit finishes reading one music data
`item, even after it is disconnected from the wireless audio
`output apparatus 11. The sound source device 12 is auto-
`matically selected again if the sound source device 13 is
`disconnected from the wireless audio output apparatus 11.
`The user can therefore enjoy listening again to the music
`represented by the music data transmitted from the sound
`source device 12 after he or she finishes talking with the
`caller, that is, after the sound source device 13 is discon-
`nected from the wireless audio output apparatus 11. The user
`need not do anything to switch the sound source from the
`sound source device 13 to the sound source device 12.
`
`[0043] The sound source device 13 can be disconnected
`from the wireless audio output apparatus 11 when the user
`pushes, for example, the on-hook button provided on the
`sound source device 13. When the on-hoof button is pushed,
`the sound source device 13 transmits a disconnection request
`to the wireless audio output apparatus 11. Upon receipt of
`this request, the apparatus 11 disconnects the device 13 from
`it.
`
`[0044] The sound source device 14, which is an audio
`guidance device, can be disconnected from the wireless
`audio output apparatus 11 whenit automatically transmits a
`disconnection request to the apparatus 11 after transmitting
`an audio messageto the wireless audio output apparatus 11.
`
`[0045] When the sound source device (#3) 14 needs to
`transmit an audio message, it transmits a wireless-connec-
`tion request to the wireless audio output apparatus 11. In
`response to the wireless-connection request,
`the wireless
`audio output apparatus 11 connects the sound source device
`(#3) 14 to it. Thereafter, the sound source device (3#) 14
`transmits a priority information item stored in it,
`to the
`wireless audio output apparatus 11. The priority information
`item represents the priority level assigned to the device (3#)
`14. Thepriority level is not fixed. The person responsible for
`the sound source device (3#) 14 (i.e., an audio guidance
`device) may push a button switch provided on the device 14
`to assign any desired priority level to the device (#3) 14. The
`sound source device (#3) 14 may be a sound source of
`emergency messages, such as evacuation orders. If so, the
`highest priority level should be assigned to the sound source
`device (#3) 14 and remain unchanged in the device (#3) 14.
`In this case, the sound source for the wireless audio output
`apparatus 11 is automatically switched from the sound
`source device 12 or 13 to the sound source device 14 when
`
`the device 14 is connected by radio to the apparatus 11 while
`the headphone 111 is generating sound from the audio data
`transmitted from the sound source device 12 or 13. Thus, the
`headphone 111 reliably generates emergency messages,
`which the user of the apparatus 11 can hear well.
`
`[0046] The sound source devices 12, 13 and 14 perform
`the same wireless audio communication function and are,
`therefore, identical in structure. Therefore, only the device
`12 will be described, with reference to FIG.2.
`
`the sound source device 12
`[0047] As FIG. 2 shows,
`comprises a memory device 21, a system control unit 22, an
`audio-data generating unit 23, a prior-connection requesting
`unit 24, and a wireless communications device 25.
`
`[0048] The memory device 21 is a nonvolatile memory
`device. It stores programs and various items of data. The
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`programs are used to control an operation of the sound
`source device 12. The memory device 21 stores priority
`information,
`too. The information represents the priority
`level assigned to the sound source device 12.
`
`[0049] The system control unit 22 is a processor that
`controls some of the other components of the sound source
`device 12. It executes the programs stored in the memory
`device 21 to control
`the audio-data generating unit 23,
`prior-connection requesting unit 24, and wireless commu-
`nications device 25. The audio-data generating unit 23
`generates audio data that should be transmitted by radio
`from the sound source device 12. In the sound source device
`12, the audio-data generating unit 23 reads and reproduces
`music data from the recording medium, thus generating the
`audio data to be transmitted.
`
`[0050] The prior-connection requesting unit 24 generates
`a priority-level notifying commandthat containsthe priority
`information item stored in the memory device 21. The
`command is transmitted via the wireless communications
`device 25 to the wireless audio output apparatus 11 after the
`sound source device 12 is connected by radio to the wireless
`audio output apparatus 11.
`
`is
`25
`communications device
`[0051] The wireless
`designed to perform wireless communication with the wire-
`less audio output apparatus 11. The device 25 comprises a
`base-band processing unit and a RF (Radio Frequency) unit.
`In responseto an instruction from the system control unit 22,
`the device 25 transmits a wireless connection request to the
`wireless audio output apparatus 11 so that the sound source
`device 12 may be connected by radio to the wireless audio
`output apparatus 11. The wireless communication between
`the apparatus 11 and the device 25 is carried out in accor-
`dance with the Bluetooth™ standards.
`
`[0052] The wireless audio output apparatus 11 may have
`the structure illustrated in FIG.3.
`
`[0053] As FIG. 3 shows, the wireless audio output appa-
`ratus 11 comprises a memory device 31, a system control
`unit 32, an audio-data generating unit 33, an audio-data
`outputting unit 34, a prior-connection request analyzing unit
`35, a sound-source switching unit 36, and a wireless com-
`munication device 37.
`
`[0054] The memory device 31 is, for example, a nonvola-
`tile memory. The device 31 stores programs and various data
`items. The programsare used to control an operation of the
`wireless audio output apparatus 11. The system control unit
`32 is a processorthat controls some of the other components
`of the wireless audio output apparatus 11. The unit 32
`executes the programs stored in the memory device 31 to
`control the audio-data generating unit 33, audio-data out-
`putting unit 34, prior-connection request analyzing unit 35,
`sound-source switching unit 36 and wireless communication
`device 37.
`
`[0055] The audio-data generating unit 33 receives a voice
`signal that the microphone 112 has generated from the user’s
`voice and converts the voice signal
`to audio data. The
`audio-data outputting unit 34 and the headphone 111 are
`devices that output sound corresponding to audio data
`transmitted from the selected sound source device.
`
`[0056] The audio-data outputting unit 34 is configured to
`receive the audio data through the system control unit 32 and
`
`supplies the same to the headphone 111. The headphone 111
`generates sounds from the audio data it has received. The
`audio-data outputting unit 34 reproduces data to accomplish
`so-called “streaming playback.” Thatis, it receives an audio
`data stream from the sound source device selected at present,
`via the wireless communication device 37 and the system
`control unit 32, and then converts the audio data stream to
`an electric signal that the headphone 111 can convert into
`sound. Thus, the audio-data outputting unit 34 converts the
`audio data, whichis a digital signal, to an analog signal. The
`analog signal is output to the headphone 111.
`
`[0057] The prior-connection request analyzing unit 35 and
`the sound-source switching unit 36 are devices that accom-
`plish the above-mentioned sound-source switching. The
`prior-connection request analyzing unit 35 analyzes the
`prior-connection request transmitted from the sound source
`device newly connected to the apparatus 11 and the prior-
`connection request transmitted from the sound source device
`selected and connected to the apparatus 11 at present. That
`is, every time a sound source device is connected to the
`apparatus 11, the unit 35 compares the prior-connection data
`contained in the prior-connection request transmitted from
`this sound source device, with the prior-connection data of
`the sound source device from which audio data is now being
`acquired.
`
`[0058] The sound-source switching unit 36 is a device that
`selects a sound source device from which the apparatus 11
`should acquire audio data, in accordance with the result of
`the comparison performed by the prior-connection request
`analyzing unit 35. The sound source device thus selected
`remains connected by radio to the wireless audio output
`apparatus 11, whereas the sound source device not selected
`is disconnected from the wireless audio output apparatus 11.
`
`[0059] The wireless communication device 37 comprises
`a base-band processing unit and a RF unit. It operates to
`establish wireless connection between the apparatus 11 and
`the sound source device that has transmitted a wireless-
`connection request, to accomplish wireless communication
`between the apparatus 11 and that sound source device. The
`wireless communication is performed in accords with the
`Bluetooth™ standards. While performing the wireless com-
`munication,
`the wireless communication device 37 can
`receive wireless-connection requests from any other sound
`source devices. Hence, whichever sound source device is
`connected at any time to the wireless audio output apparatus
`11, the wireless audio output apparatus 11 can select the
`sound source device that has a higher priority level than any
`other sound source device connected to the apparatus 11 at
`that time.
`
`[0060] How the wireless audio output apparatus 11
`switches the sound source will be explained, with reference
`to the flowchart of FIGS.4 and 5.
`
`[0061] Any oneof the sound source devices 12, 13 and 14
`may receive a request for transmitting audio data (YESat
`Step S111 shown in FIG. 4). The sound source device
`transmits a wireless-connection request to the wireless audio
`output apparatus 11 and starts a procedure to establish
`wireless connection betweenit and the wireless audio output
`apparatus 11 (Step S112). Also, the apparatus 11 starts a
`procedure to establish the wireless connection (Step $113).
`At Steps $112, $113, a physical wireless link is established
`between the wireless communication device 37 of the appa-
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`ratus 11 and the wireless communications device 25 of the
`sound source device that has transmitted the wireless-con-
`
`nection request.
`
`[0062] The sound source device (#1) 12 is triggered when
`the user instructs that audio data be reproduced. Thus
`triggered, the device (#1) 12 transmits a wireless-connection
`request to the wireless audio output apparatus 11. The sound
`source device (#2) 13 is triggered when it receives a call
`from, for example, the mobile phone network. Thustrig-
`gered, the device (#2) 13 transmits a wireless-connection
`request to the wireless audio output apparatus 11.
`
`In any sound source device that is connected by
`[0063]
`radio to the wireles