Abstract:
Herein disclosed a sound inputting and outputting apparatus for being connected to an external apparatus which includes a noise cancel signal production section, a storage section and a reproduction section, including: a first auricle mounting section; a second auricle mounting section; and a plug.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present invention contains subject matter related to Japanese Patent Application JP 2006-243903 filed in the Japan Patent Office on Sept. 8, 2006, the entire contents of which being incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to a plug, a sound inputting and outputting apparatus and a noise cancel system, and more particularly to a plug of a five-pole configuration and a sound inputting and outputting apparatus and a noise cancel system in which a plug of a five-pole configuration is used. 
         [0004]    2. Description of the Related Art 
         [0005]    A plug to be connected to a jack of various electronic equipments such as, for example, an acoustic equipment is provided at an end portion of, for example, an earphone, a headphone, or various connection cables. 
         [0006]    Generally, such a plug as described above such as, for example, a plug provided on an earphone, a headphone or the like, has a three-pole configuration for a speaker L (left), a speaker R (right) and the ground as disclosed, for example, in Japanese Patent Laid-Open No. Hei 9-204966 (hereinafter referred to as Patent Document 1). 
         [0007]    A sound inputting and outputting apparatus such as an earphone or a headphone in which such a plug as described above is provided includes a pair of auricle mounting portions for being mounted on a pair of auricles of a user. However, when sound is outputted from a pair of speakers of the sound inputting and outputting apparatus in a state wherein the auricle mounting portions are mounted on the auricles of the user, such a disadvantage sometimes occurs that external sound is inputted as noise to the auricles depending upon the external environment or the like. 
         [0008]    Countermeasures for canceling such noise are available in the related art. According to one of the related art, a microphone and a circuit board on which a noise cancel circuit is formed are disposed in each of the auricle mounting portions of the sound inputting and outputting apparatus. The noise cancel circuit produces a noise cancel signal based on a noise signal inputted to the microphone, and the noise cancel signal is outputted from the speaker provided in each of the auricle mounting portions to cancel the noise. 
       SUMMARY OF THE INVENTION 
       [0009]    However, according to the related art for canceling noise, not only a microphone but also a circuit board on which a noise cancel circuit is formed are disposed in each of the auricle mounting portions of the sound inputting and outputting apparatus. Therefore, the auricle mounting portions have a size increased as much, and this gives rise to a problem that the feeling of the user in mounting of the auricle mounting portions on the auricles is not good. 
         [0010]    On the contrary, if it is tried to miniaturize the auricle mounting portions, then it becomes difficult to assure the space for arrangement of the circuit board, resulting in failure to achieve cancellation of noise. 
         [0011]    Therefore, it is demanded to provide a plug, a sound inputting and outputting apparatus and a noise cancel system wherein a noise cancel function can be achieved. 
         [0012]    According to the present invention, in order to achieve a noise cancel function, a plug of a five-pole configuration is used. 
         [0013]    More particularly, according to an embodiment of the present invention, there is provided a plug for being inserted in a jack of an external apparatus which includes a noise cancel signal production section and a reproduction section to establish connection of first and second microphones and first and second speakers provided in a sound inputting and outputting apparatus to the external apparatus, including a first conductor configured to transmit a first noise signal to the external apparatus in response to first noise inputted to the first microphone, a second conductor configured to transmit a second noise signal to the external apparatus in response to second noise inputted to the second microphone, a third conductor configured to transmit a first synthesis signal of a first noise cancel signal produced by the noise cancel signal production section in response to the first noise signal and a first sound signal reproduced by the reproduction section to the first speaker, a fourth conductor for grounding, and a fifth conductor configured to transmit a second synthesis signal of a second noise cancel signal produced by the noise cancel signal production section in response to the second noise signal and a second sound signal reproduced by the reproduction section to the second speaker. 
         [0014]    According to another embodiment of the present invention, there is provided a sound inputting and outputting apparatus for being connected to an external apparatus which includes a noise cancel signal production section for producing, in response to a noise signal inputted thereto, a noise cancel signal for reducing the noise signal, a storage section and a reproduction section for reproducing sound data stored in the storage section, including a first auricle mounting section including a first microphone and a first speaker, a second auricle mounting section including a second microphone and a second speaker, and a plug including a first conductor configured to output a first noise signal to the external apparatus in response to first noise inputted to the first microphone, a second conductor configured to output a second noise signal to the external apparatus in response to second noise inputted to the second microphone, a third conductor configured to transmit a first synthesis signal of a first noise cancel signal produced by the noise cancel signal production section in response to the first noise signal and a first sound signal reproduced by the reproduction section to the first speaker, a fourth conductor for grounding, and a fifth conductor configured to transmit a second synthesis signal of a second noise cancel signal produced by the noise cancel signal production section in response to the second noise signal and a second sound signal reproduced by the reproduction section to the second speaker, the plug being configured to be inserted into a jack provided on the external apparatus to establish connection thereof to the external apparatus. 
         [0015]    According to a further embodiment of the present invention, there is provided a sound signal processing apparatus including a noise cancel signal production section configured to produce first and second noise cancel signals in response to first and second noise signals outputted from first and second microphones of a sound inputting and outputting apparatus in response to first noise and second nose inputted to the first and second microphones, respectively, a reproduction section configured to reproduce sound data stored in a storage section and output first and second sound signals, a synthesis section configured to synthesize the first and second noise cancel signals with the first and second sound signals to produce first and second synthesis signals, respectively, and a jack configured to be fitted with a plug of a five-pole configuration provided on the sound inputting and outputting apparatus and including a first conductor configured to transmit the first noise signal outputted from the first microphone, a second conductor configured to transmit the second noise signal outputted from the second microphone, a third conductor configured to transmit the first synthesis signal to the first speaker of the sound inputting and outputting apparatus, a fourth conductor for grounding, and a fifth conductor configured to transmit the second synthesis signal to the second speaker of the sound inputting and outputting apparatus. 
         [0016]    According to a still further embodiment of the present invention, there is provided a noise cancel system including a sound signal processing apparatus, and a sound signal inputting and outputting apparatus, the sound signal processing apparatus including a noise cancel signal production section configured to produce a noise cancel signal in response to a noise signal inputted thereto, a reproduction section configured to reproduce a sound signal stored in a storage section, and a jack, the sound signal inputting and outputting apparatus including a first auricle mounting section including a first microphone and a first speaker, a second auricle mounting section including a second microphone and a second speaker, and a plug of a five-pole configuration including a first conductor configured to output a first noise signal to the sound signal processing apparatus in response to first noise inputted to the first microphone, a second conductor configured to output a second noise signal to the sound signal processing apparatus in response to second noise inputted to the second microphone, a third conductor configured to transmit a first synthesis signal of a first noise cancel signal produced by the noise cancel signal production section in response to the first noise signal and a first sound signal reproduced by the reproduction section to the first speaker, a fourth conductor for grounding, and a fifth conductor configured to transmit a second synthesis signal of a second noise cancel signal produced by the noise cancel signal production section in response to the second noise signal and a second sound signal reproduced by the reproduction section to the second speaker, the plug being configured to be inserted into a jack provided of the sound signal processing apparatus to establish connection between the sound inputting apparatus and the sound signal processing apparatus. 
         [0017]    In the plug, sound inputting and outputting apparatus, sound signal processing apparatus and noise cancel system, first and second noise cancel signals are transmitted from the noise cancel signal production section provided in the external apparatus to the first and second speakers, respectively. 
         [0018]    The above and other features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements denoted by like reference symbols. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0019]      FIG. 1  is a schematic view showing a general configuration of a sound inputting and outputting apparatus to which the present invention is applied and an external apparatus; 
           [0020]      FIG. 2  is an enlarged perspective view showing a plug to which the present invention is applied; 
           [0021]      FIG. 3  is an enlarged side elevational view of the plug; 
           [0022]      FIG. 4  is an enlarged side elevational view of the plug as viewed from a direction different from that in  FIG. 3 ; 
           [0023]      FIG. 5  is an enlarged sectional view of the plug; 
           [0024]      FIG. 6  is an enlarged sectional view of the plug taken a direction different from that in  FIG. 5 . 
           [0025]      FIG. 7  is an enlarged perspective view showing a fourth insulator and a fifth conductor of the plug; 
           [0026]      FIG. 8  is an enlarged perspective view of a jack of the external apparatus; 
           [0027]      FIG. 9  is a sectional view taken along line IX-IX of  FIG. 8 ; 
           [0028]      FIG. 10  is a sectional view taken along line X-X of  FIG. 8 ; 
           [0029]      FIG. 11  is an enlarged sectional view of the plug in a state wherein it is connected to the jack; 
           [0030]      FIG. 12  is an enlarged sectional view showing the plug in the state wherein it is connected to the jack as viewed from a direction different from that in  FIG. 11 ; 
           [0031]      FIG. 13  is a block diagram showing an internal configuration of the sound inputting and outputting apparatus and the external apparatus; 
           [0032]      FIG. 14  is an enlarged side elevational view showing a plug having a three-pole configuration; 
           [0033]      FIG. 15  is an enlarged sectional view showing the plug of a three-pole configuration in a state wherein it is connected to the jack; 
           [0034]      FIG. 16  is an enlarged sectional view showing the plug of a three-pole configuration wherein it is connected to the jack as viewed from a direction different from that in  FIG. 15 ; and 
           [0035]      FIG. 17  is a graph illustrating a noise signal and a noise cancel signal. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    Referring first to  FIG. 1 , there is shown a sound inputting and outputting apparatus  1  to which the present invention is applied. The sound inputting and outputting apparatus  1  may be, for example, an earphone or a headphone as seen in  FIG. 1  and includes a pair of auricle mounting elements  2  and  3  for being mounted on the left and right auricles  100  and  200  of a user, respectively, and a plug  5  connected to the auricle mounting elements  2  and  3  through a connection cable  4 . 
         [0037]    The auricle mounting element  2  is mounted typically on the left side auricle  100  of the user. The auricle mounting element  2  has a first microphone  6  and a first speaker  7  built therein. The first microphone  6  is disposed typically on the outer side with respect to the first speaker  7  remote from the drum membrane of the user. In other words, the first microphone  6  is disposed remotely from the sound outputting side of the first speaker  7  with respect to the first speaker  7 . 
         [0038]    The auricle mounting element  3  is mounted typically on the right side auricle  200 . The auricle mounting element  3  has a second microphone  8  and a second speaker  9  built therein. The second microphone  8  is disposed typically on the outer side with respect to the second speaker  9  remote from the drum membrane of the user. In other words, the second microphone  8  is disposed remotely from the sound outputting side of the second speaker  9  with respect to the second speaker  9 . 
         [0039]    The connection cable  4  includes five connection lines hereinafter described which are covered with an insulating material. 
         [0040]    The plug  5  is partly covered with a cover  10  formed from a material having no electric conductivity such as, for example, a resin material. 
         [0041]    Referring now to  FIGS. 2 to 4 , the plug  5  includes a first conductor  11 , a first insulator  12 , a second conductor  13 , a second insulator  14 , a third conductor  15 , a third insulator  16 , a fourth conductor  17 , a fourth insulator  18  and a fifth conductor  19 . The first, second, third, fourth and fifth conductors  11 ,  13 ,  15 ,  17  and  19  are made of a metal material having high electrical conductivity. Meanwhile, the first, second, third and fourth insulators  12 ,  14 ,  16  and  18  are made of a material which does not have electrical conductivity such as a resin material or the like. 
         [0042]    The first, second, third, fourth and fifth conductors  11 ,  13 ,  15 ,  17  and  19  are used, for example, as a terminal for the first speaker  7 , a terminal for the second speaker  9 , a terminal for the first microphone  6 , a grounding terminal and a terminal for the second microphone  8 , respectively. 
         [0043]    It is to be noted that, while the first, second, third, fourth and fifth conductors  11 ,  13 ,  15 ,  17  and  19  are described as being used, for example, as a terminal for the first speaker  7 , a terminal for the second speaker  9 , a terminal for the first microphone  6 , a grounding terminal and a terminal for the second microphone  8 , respectively, it may be determined arbitrarily as what terminals the first, second, third, fourth and fifth conductors  11 ,  13 ,  15 ,  17  and  19  should individually be used. 
         [0044]    The first conductor  11  is formed as a substantially round bar and has an electrode portion  11   a  of a large diameter and a fitting portion  11   b  of a small diameter. The first conductor  11  has a flange portion  11   c  provided between thereon the electrode portion  11   a  and the fitting portion  11   b  in such a manner as to be swollen outwardly. The first conductor  11  further has a cable connection portion  11   d  provided at an end portion of the fitting portion  11   b  thereof remote from the flange portion  11   c.    
         [0045]    The first conductor  11  further has an inclination face  11   e  formed on the outer periphery of the electrode portion  11   a  thereof such that it is inclined so as to displace to the center side of the round bar toward the fitting portion  11   b.  The length of the fitting portion  11   b  in the axial direction is greater than that of the electrode portion  11   a.  The diameter of the cable connection portion  11   d  is smaller than that of the electrode portion  11   a  but greater than that of the fitting portion  11   b.    
         [0046]    The first insulator  12  is formed in a substantially cylindrical shape and has a large diameter portion  12   a  provided at an end portion of the first insulator  12  in the axial direction and having an outer diameter greater than that of the other portion which is therefore formed as a small diameter portion  12   b.  The large diameter portion  12   a  is formed with a thickness greater than that of the small diameter portion  12   b.  A swollen portion  12   c  is formed at an end portion of the small diameter portion  12   b  remote from the large diameter portion  12   a  such that it is swollen a little outwardly in a radial direction of the round bar. Further, a shallow fitting concave portion  12   d  is formed on the outer face side of the first insulator  12  between the large diameter portion  12   a  and the swollen portion  12   c.    
         [0047]    The first insulator  12  is outwardly fitted with the fitting portion  1   b  of the first conductor  11 . In this state wherein the first insulator  12  is outwardly fitted with the first conductor  11 , the outer circumferential face of the large diameter portion  12   a  coincides with that of the flange portion  11   c.  The electrode portion  11   a,  flange portion  11   c  and cable connection portion  11   d  of the first conductor  11  are exposed to the outside. 
         [0048]    The second conductor  13  is formed in a substantially cylindrical shape and has an electrode portion  13   a  of a large diameter and a fitting portion  13   b  of a small diameter. A substantially annular connection portion  13   c  is formed on the first conductor  13  such that it connects the electrode portion  13   a  and the fitting portion  13   b  to each other. Further, a cable connection portion  13   d  is provided at an end of the fitting portion  13   b  remote from the connection portion  13   c.    
         [0049]    The second conductor  13  is outwardly fitted with the first insulator  12 . In the state wherein the second conductor  13  is outwardly fitted with the first insulator  12 , the electrode portion  13   a  is connected to a portion of the large diameter portion  12   a  other than one end portion and the fitting portion  13   b  and the connection portion  13   c  are connected to the fitting concave portion  12   d  Further, the outer circumferential face of the fitting portion  13   b  coincides with that of the swollen portion  12   c.  Accordingly, part of the large diameter portion  12  and the swollen portion  12   c  of the second insulator  12  are exposed to the outside. 
         [0050]    The second insulator  14  is formed in a substantially cylindrical shape and has a large diameter portion  14   a  provided at an end portion thereof in the axial direction and having a diameter greater than that of the other portion, which is provided as a small diameter portion  14   b.  The large diameter portion  14   a  is formed with a thickness greater than that of the small diameter portion  14   b.  A swollen portion  14   c  is provided at an end portion of the small diameter portion  14   b  remote from the large diameter portion  14   a  and is swollen outwardly a little. Further, a shallow fitting concave portion  14   d  is formed on the outer face side of the second insulator  14  between the large diameter portion  14   a  and the swollen portion  14   c.    
         [0051]    The second insulator  14  is outwardly fitted with the fitting portion  13   b  of the second conductor  13 . In the state wherein the second insulator  14  is fitted with the second conductor  13 , the outer circumferential face of the large diameter portion  14   a  coincides with that of the electrode portion  13   a  in a radial direction. The electrode portion  13   a  and the cable connection portion  13   d  of the second conductor  13  are exposed to the outside. 
         [0052]    The third conductor  15  is formed in a substantially cylindrical shape and has a large diameter electrode portion  15   a  and a small diameter fitting portion  15   b.  A substantially annular connection portion  15   c  is provided on the first conductor  15  and connects the electrode portion  15   a  and the fitting portion  15   b  to each other. Further, a cable connection portion  15   d  is provided at an end portion of the fitting portion  15   b  remote from the connection portion  15   c.    
         [0053]    The third conductor  15  is outwardly fitted with the second insulator  14 . In the state wherein the third conductor  15  is outwardly fitted with the second insulator  14 , the third conductor  15  is connected to the fitting concave portion  14   d  and the outer circumferential face of the electrode portion  15   a  coincides with that of the large diameter portion  14   a  in a radial direction. Further, the outer circumferential face of the fitting portion  15   b  coincides with that of the swollen portion  14   c  in a radial direction. Accordingly, the large diameter portion  14   a  and the swollen portion  14   c  of the second insulator  14  are exposed to the outside. 
         [0054]    The third insulator  16  is formed in a substantially cylindrical shape, and a large diameter portion  16   a  having a large outer diameter is provided one end portion of the third insulator  16  in the axial direction. A portion of the third insulator  16  contiguous to the large diameter portion  16   a  in the axial direction is formed as a small diameter portion  16   b,  and the other end portion of the third insulator  16  in the axis direction is formed as a swollen portion  16   c  having an outer diameter greater than that of the small diameter portion  16   b.  The large diameter portion  16   a  and the swollen portion  16   c  are formed with a thickness greater than that of the small diameter portion  16   b.  A shallow fitting concave portion  16   d  is formed on the outer face side of the third insulator  16  between the large diameter portion  16   a  and the swollen portion  16   c.    
         [0055]    The third insulator  16  is outwardly fitted with the fitting portion  15   b  of the third conductor  15 . In the state wherein the third insulator  16  is outwardly fitted with the third conductor  15 , the outer circumferential faces of the large diameter portion  16   a  and the swollen portion  16   c  coincide with the outer periphery of the electrode portion  15   a  in a radial direction. In the third conductor  15 , the electrode  15   a  and the cable connection portion  15   d  are exposed. 
         [0056]    The fourth conductor  17  is formed in a substantially cylindrical shape and has an electrode portion  17   a  and an annular projection  17   b  provided in an outwardly projecting manner on the outer circumferential face at a central portion of the electrode portion  17   a  in the axial direction. A cable connection portion  17   c  is provided at a portion of the electrode portion  17   a.    
         [0057]    The fourth conductor  17  is outwardly fitted with the fitting concave portion  16   d  of the third insulator  16 . In the state wherein the fourth conductor  17  is outwardly fitted with the third insulator  16 , the outer circumferential face of the electrode portion  17   a  coincides with those of the large diameter portion  16  and the swollen portion  16   c  in a radial direction. Accordingly, the large diameter portion  16   a  and the swollen portion  16   c  of the third insulator  16  are exposed to the outside. 
         [0058]    A conductor attachment portion  20  and an extension  21  are formed integrally on the outer periphery of the fourth insulator  18  as seen in  FIGS. 4 and 6 . 
         [0059]    The conductor attachment portion  20  is formed long in one direction and has a main body portion  20   a  and a pair of projections  20   b  projecting in a lateral direction away from each other from an end portion of the main body portion  20   a  in a longitudinal direction. A conductor attachment groove  20   c  is formed on the main body portion  20   a  and extends in the longitudinal direction, and a fitting groove  20   d  is formed on the face of the conductor attachment portion  20  opposite to the face on which the conductor attachment groove  20   c  is formed and extends in the widthwise direction. The extension  21  is projected from an end face of the conductor attachment portion  20  in the longitudinal direction toward a direction perpendicular to the projection direction of the projections  20   b.    
         [0060]    The fourth insulator  18  is attached at the conductor attachment portion  20  thereof to part of the outer periphery of a portion of the third insulator  16  which extends from the large diameter portion  16   a  to the swollen portion  16   c.  Further, the fourth insulator  18  is attached at the extension  21  thereof to part of the outer periphery of a portion of the third conductor  15  which extends from the cable connection portion  15   d  to the swollen portion  12   c  of the first insulator  12 . In the state wherein the fourth insulator  18  is attached in this manner, the fitting groove  20   d  is fitted with the projection  17   b  of the fourth conductor  17  and the conductor attachment portion  20  is positioned on the outer circumference side with respect to the extension  21 . 
         [0061]    The fifth conductor  19  is formed as a plate extending in one direction and has blocking projections  19   a  provided at an intermediate portion thereof in the longitudinal direction and projected away from each other. One side of the fifth conductor  19  with reference to the blocking projections l 9   a  serves as an insertion portion  19   b  while the other side serves as a cable connection portion  19   c.  A connection projection  19   d  projected in a thicknesswise direction is provided at an end of the insertion portion  19   b  remote from the cable connection portion  19   c.    
         [0062]    The fifth conductor  19  is attached to the fourth insulator  18  by inserting the insertion portion  19   b  in the conductor attachment groove  20   c  as seen in  FIG. 3 . In the state wherein the fifth conductor  19  is attached to the fourth insulator  18 , the blocking projections  19   a  thereof contact with one end face of the main body portion  20   a  and the cable connection portion  19   c  is positioned in a spaced relationship away from the extension  21  to the outer periphery side as seen in  FIG. 4 . 
         [0063]    Referring to  FIGS. 5 and 6 , in the plug  5  having the configuration described above, five connection lines  4   a,    4   b,    4   c,    4   d  and  4   e  of the connection cable  4  are connected at one end portion thereof to the cable connection portions lid,  13   d,    15   d,    17   c  and  19   c  of the first, second, third, fourth and fifth conductors  11 ,  13 ,  15 ,  17  and  19 , respectively, by means of, for example, soldering. The connection lines  4   a,    4   b,    4   c,    4   d  and  4   e  are connected at the other end thereof, for example, to the first speaker  7 , second speaker  9 , first microphone  6 , grounding terminal not shown and second microphone  8 , respectively. 
         [0064]    In the state wherein the connection lines  4   a,    4   b,    4   c,    4   d  and  4   e  are connected to the respective portions of the plug  5 , a portion of the fourth conductor  17  which extends from the projection  17   b  to the cable connection portion  11   d  of the first conductor  11  is covered with a cover  10  to close up and the cable connection portions  11   d,    13   d,    15   d,    17   c  and  19   c  as seen in  FIG. 2 . 
         [0065]    The plug  5  is connected to the jack  23  provided on the external equipment  22 , which may be, for example, a music reproduction equipment, as seen in  FIG. 1 . 
         [0066]    Referring to  FIG. 8 , the jack  23  includes a housing  24  on which several components are provided. A plug insertion hole  24   a  is formed on the housing  24  such that it is open in one direction. Five terminal pieces  25  are projected from an end portion of the jack  23  remote from the opening of the plug insertion hole  24   a.  The terminal pieces  25  are connected to a control circuit hereinafter described which is provided on the external equipment  22 . 
         [0067]    Referring to  FIGS. 9 and 10 , the first, second, third, fourth and fifth connection terminals  26 ,  27 ,  28 ,  29  and  30  are disposed in the inside of the jack  23 . 
         [0068]    Referring to  FIG. 9 , the first connection terminal  26  has a base portion  26   a  disposed along the inner face of the jack  23 , and a base end portion  26   b  folded back from the base portion  26   a  and extending in a direction away from the plug insertion hole  24   a.  The first connection terminal  26  further has a leaf spring portion  26   c  contiguous to the base end portion  26   b  and bent in a direction away from the base portion  26   a  with respect to the base end portion  26   b.  An end portion of the leaf spring portion  26   c  is formed as a connection portion  26   d.    
         [0069]    Referring to  FIG. 10 , the second connection terminal  27  has a base end portion  27   a  disposed in parallel to the inner face of the jack  23 , and a leaf spring portion  27   b  contiguous to the base end portion  27   a  and bent in a direction away from the inner face of the jack  23  with respect to the base end portion  27   a.  The second connection terminal  27  further has a connection portion  27   c  provided an end portion of the leaf spring portion  27   b  thereof. The connection portion  27   c  is positioned on the plug insertion hole  24   a  side with respect to the connection portion  26   d  of the first connection terminal  26 . 
         [0070]    Referring to  FIG. 9 , the third connection terminal  28  has a base end portion  28   a  disposed along the inner face of the jack  23  and a leaf spring portion  28   b  contiguous to the base end portion  28   a  and curved in a direction away from the inner face of the jack  23  with respect to the base end portion  28   a.  A connection portion  28   c  is provided at an end portion of the leaf spring portion  28   b.  The connection portion  28   c  is positioned on the plug insertion hole  24   a  side with respect to the connection portion  27   c  of the second connection terminal  27 . 
         [0071]    Referring to  FIGS. 9 and 10 , the fourth connection terminal  29  has a base end portion  29   a  disposed along the inner face of the jack  23 , and a leaf spring portion  29   b  contiguous to the base end portion  29   a  and bent in a direction away from the inner face of the jack  23  with respect to the base end portion  29   a.  A connection portion  29   c  is provided at an end portion of the leaf spring portion  29   b.  The connection portion  29   c  is positioned adjacent the plug insertion hole  24   a  with respect to the connection portion  28   c  of the third connection terminal  28  and just on the inner side of the opening of the plug insertion hole  24   a.    
         [0072]    Referring to  FIG. 10 , the fifth connection terminal  30  has a base end portion  30   a  disposed along the inner side of the jack  23 , and a leaf spring portion  30   b  contiguous to the base end portion  30   a  and bent in a direction away from the inner face of the jack  23  with respect to the base end portion  30   a.  A connection portion  30   c  is provided at an end portion of the leaf spring portion  30   b.  The connection portion  30   c  is positioned just on the inner side of the opening of the plug insertion hole  24   a.    
         [0073]    A stopper wall  31  is provided inside the jack  23 . The stopper wall  31  is positioned remotely from the inner face of the jack  23  with respect to the leaf spring portion  30   b  of the fifth connection terminal  30 . 
         [0074]    Referring to  FIGS. 9 and 10 , a retaining insulating member  32  is provided inside the jack  23 . The retaining insulating member  32  is provided at an end portion of the plug insertion hole  24   a  remote from the opening. 
         [0075]    The first, second third fourth and fifth connection terminals  26 ,  27 ,  28 ,  29  and  30  are retained with a portion thereof embedded in the retaining insulating member  32  and are individually connected to the terminal pieces  25 . Accordingly, the first, second third fourth and fifth connection terminals  26 ,  27 ,  28 ,  29  and  30  are connected to the control circuit provided in the external apparatus  22  through the respective terminal pieces  25 . 
         [0076]    Referring to  FIGS. 11 and 12 , when the plug  5  is inserted in the plug insertion hole  24   a,  the electrode portion  11   a  of the first conductor  11 , electrode portion  13   a  of the second conductor  13 , electrode portion  15   a  of the third conductor  15 , electrode portion  17   a  of the fourth conductor  17  and connection projection  19   d  of the fifth conductor  19  are connected to the connection portion  26   d  of the first connection terminal  26  for the first speaker  7 , connection portion  27   c  of the second connection terminal  27  for the second speaker  9 , connection portion  28   c  of the third connection terminal  28  for the first microphone  6 , connection portion  29   c  of the fourth connection terminal  29  for grounding, and connection portion  30   c  of the fifth connection terminal  30  for the second microphone  8 , respectively. 
         [0077]    At this time, the plug  5  is inserted to a position at which the projection  17   b  of the fourth conductor  17  contacts with the outer side opening edge of the plug insertion hole  24   a  of the jack  23  and one end face of the insertion portion  19   b  of the fifth conductor  19  contacts with the stopper wall  31 . Thus, the plug  5  is positioned with respect to the jack  23  in the insertion direction. 
         [0078]    The connection portions  26   d,    27   c,    28   c,    29   c  and  30   c  are resiliently deformed against the spring force with respect to the base end portions  26   b,    27   a,    28   a,    29   a  and base end portion  30   a,  respectively, and are connected in a state wherein they are pressed against the electrode portion  11   a,  electrode portion  13   a,  electrode portion  15   a,  electrode portion  17   a  and connection projection  19   d.    
         [0079]    Referring to  FIG. 13 , the external apparatus  22  includes an operation section  33 , a plug detection section  34 , a storage section  35  and a power supply section  36 . 
         [0080]    The operation section  33  includes operation buttons, operation switches and like members for executing various functions such as variation of the sound volume, variation of the sound quality, selection of sound to be reproduced such as selection of a musical piece and so forth. 
         [0081]    The plug detection section  34  has a function of detecting a type of a plug inserted in and connected to the jack  23 . The plug in this instance may be the plug  5  of the five-pole type having the configuration described hereinabove or a plug of a three-pole configuration, and the plug detection section  34  detects which one of the types the type of the plug connected to the jack  23  is. 
         [0082]    The storage section  35  is, for example, a flash memory and stores not only sound signals but also programs and so forth required by the external apparatus  22 . 
         [0083]    The power supply section  36  typically is a battery and supplies necessary power to the components of the external apparatus  22 . 
         [0084]    The external apparatus  22  includes a control circuit  37  and operates with power supplied thereto from the power supply section  36 . The control circuit  37  includes a control section  38 , a reproduction section  39 , a noise cancel signal production section  40  and a synthesis section  41 . 
         [0085]    The control section  38  controls the entire external apparatus  22 . For example, the control section  38  signals an instruction signal for canceling noise to the noise cancel signal production section  40  based on a result of detection of the plug detection section  34 . Further, the control section  38  signals various instruction signals to the components of the external apparatus  22  such as the reproduction section  39  in response to an operation received from the operation section  33 . 
         [0086]    The reproduction section  39  reproduces sound data stored in the storage section  35  in response to an instruction signal received from the control section  38  and outputs the reproduced sound data to the synthesis section  41 . Thus, the synthesis section  41  produces and outputs first and second sound signals to the first and second speakers  7  and  9 , respectively 
         [0087]    The noise cancel signal production section  40  produces, in response to an instruction signal received from the control section  38 , first and second noise cancel signals for first and second noise signals inputted thereto from the control section  38  through the plug  5  and the jack  23 . The noise cancel signal production section  40  signals the thus produced noise cancel signals to the synthesis section  41 . 
         [0088]    The synthesis section  41  synthesizes, in response to an instruction signal received from the control section  38 , first and second sound signals inputted thereto from the reproduction section  39  and first and second noise cancel signals inputted thereto from the noise cancel signal production section  40  to produce first and second synthesis signals, respectively. Then, the noise cancel signal production section  40  signals the first synthesis signal to the first speaker  7  of the sound inputting and outputting apparatus  1  through the jack  23  and the plug  5  and signals the second synthesis signal to the second speaker  9  of the sound inputting and outputting apparatus  1  through the jack  23  and the plug  5 . 
         [0089]    The external apparatus  22  has a display section  22   a  provided thereon as seen in  FIG. 1 . Referring to  FIG. 1 , the display section  22   a  displays not only various functions carried out in response to an operation for the operation section  33  and a current execution state of a function but also the type of a plug connected to the jack  23  and so forth. Further, the display section  22   a  displays information regarding the noise cancel function, which is hereinafter described, such as, for example, information that the noise cancel function is executed in a state wherein the plug  5  is connected to the jack  23 . 
         [0090]    Referring back to  FIG. 13 , if noise such as external noise is inputted to the first and second microphones  6  and  8  of the external apparatus  22 , then noise signals based on the noise are inputted from the first and second microphones  6  and  8  to the noise cancel signal production section  40  through the connection cable  4 , plug  5  and jack  23 . 
         [0091]    When the noise signals are inputted to the noise cancel signal production section  40 , the control section  38  operates based on a result of detection, that is, based on a detection signal, signaled from the plug detection section  34  to the control section  38 . 
         [0092]    At this time, if a detection signal that the plug  5  of the five-pole type is connected to the jack  23  is signaled from the plug detection section  34 , then the control section  38  controls the noise cancel signal production section  40  to produce a noise cancel signal. 
         [0093]    On the other hand, if another detection signal that a plug of the three-pole type is connected to the jack  23  is signaled from the plug detection section  34 , then the control section  38  controls the noise cancel signal production section  40  so as not to execute a noise cancel signal process. Accordingly, where a plug of the three-pole configuration is connected to the jack  23 , no noise cancel signal is produced. 
         [0094]    Referring now to  FIGS. 14 to 16 , there is shown a plug  50  of the three-pole type. The plug  50  of the three-pole type shown includes a first conductor  51 , a first insulator  52  outwardly fitted on the first conductor  51 , a second conductor  53  outwardly fitted on the first insulator  52 , a second insulator  54  outwardly fitted on the second conductor  53  and a third conductor  55  outwardly fitted on the second insulator  54 . In a state wherein the plug  50  is connected to the jack  23 , the first conductor  51  is connected to the first connection terminal  26  for the first speaker  7  and the second conductor  53  is connected to the second connection terminal  27  for the second speaker  9  while the third conductor  55  is connected to the fourth connection terminal  29  for grounding. The plug  50  is not connected to the fifth connection terminal  30  for the second microphone  8 . 
         [0095]    While the plug  50  is configured such that the third conductor  55  thereof contacts also with the third connection terminal  28  for the first microphone  6 , the control circuit  37  of the external apparatus  22  is configured such that no signal is communicated between the third conductor  55  and the third connection terminal  28 . It is to be noted that, for example, the arrangement position of the third connection terminal  28  of the jack  23  may be changed so that, when the plug  50  is connected to the jack  23 , the third conductor  55  is not connected to the third connection terminal  28 . 
         [0096]    If an instruction signal to produce a noise cancel signal is signaled from the control section  38  to the noise cancel signal production section  40  as described hereinabove, then a noise cancel signal n′ which has a phase opposite to that of a noise signal n as seen in  FIG. 17  is produced by the noise cancel signal production section  40 . 
         [0097]    After the noise cancel signal is produced by the noise cancel signal production section  40 , it is signaled to the synthesis section  41 . Simultaneously, a sound signal is signaled from the reproduction section  39  to the synthesis section  41 . Consequently, the synthesis section  41  produces a synthesis signal wherein the noise cancel signal and the sound signal are synthesized. 
         [0098]    The thus produced synthesis signal (first and second synthesis signals) is signaled from the synthesis section  41  to the first and second speakers  7  and  9  of the sound inputting and outputting apparatus  1  through the jack  23 , plug  5  and connection cable  4 . 
         [0099]    After the synthesis signal is signaled to the first and second speakers  7  and  9 , the sound signal is inputted to the auricles  100  and  200  of the user in a state wherein the noise inputted from the outside is cancelled by the noise cancel signal. 
         [0100]    As described above, in the sound inputting and outputting apparatus  1 , the plug  5  has a five-pole configuration and noise cancellation is performed by the control circuit  37  of the external apparatus  22 . Consequently, miniaturization of the sound inputting and outputting apparatus  1  is assured and execution of the noise cancel function can be assured simultaneously. 
         [0101]    Further, since, in the plug  5 , the five-pole configuration is achieved by attaching an electrode to an outer circumferential face of a four-pole configuration portion having a shape of a substantially round bar, the plug  5  of the five-pole configuration can be formed readily. 
         [0102]    Furthermore, since, in the plug  5 , the fifth conductor  19  is formed like a plate and attached at one face thereof in a thicknesswise direction to the fourth insulator  18 , the overall outer diameter of the plug  5  can be reduced. Consequently, miniaturization can be anticipated. 
         [0103]    Further, since the connecting projection  19   d  which functions as an electrode element is provided on the fifth conductor  19 , good connection performance can be assured between the fifth conductor  19  and the fifth connection terminal  30  of the jack  23 . 
         [0104]    Further, since, in the plug  5 , the fourth insulator  18  and the fifth conductor  19  are attached to the four-pole configuration portion formed as a substantially round bar, the fourth insulator  18  and the fifth conductor  19  are so shaped as to project forwardly from the substantially round bar portion. Consequently, insertion in error into a jack for exclusive use with a plug of the three-pole configuration wherein the plug insertion hole is formed in a circular shape can be prevented. 
         [0105]    In the sound inputting and outputting apparatus  1 , since the first and second microphones  6  and  8  are disposed on the outer side with respect to the first and second speakers  7  and  9 , respectively, the first and second microphones  6  and  8  are positioned remotely from the drum membrane of the user with respect to the first and second speakers  7  and  9 , respectively. Consequently, execution of noise cancellation can be carried out by feedforward type control. 
         [0106]    Further, in the external apparatus  22 , the plug detection section  34  for detecting the connection state of a plug to the jack  23  is provided such that the noise cancel function is executed when the plug  5  of the five-pole configuration is connected to the jack  23 . Consequently, when the plug  50  of the three-pole configuration is connected to the jack  23 , the noise cancel function is not executed. Consequently, simplification of control by prevention of execution of an unnecessary function can be achieved. 
         [0107]    Further, in the external apparatus  22 , when it is detected by the plug detection section  34  that the plug  5  is connected to the jack  23 , the information that the noise cancel function is executed is displayed on the display section  22   a  of the external apparatus  22 . Consequently, the user can confirm that the noise cancel function is executed, and accordingly, improvement in convenience in use can be anticipated. 
         [0108]    It is to be noted that a display section may be provided on the sound inputting and outputting apparatus  1 . In this instance, when it is detected by the plug detection section  34  that the plug  5  is connected to the jack  23 , the information that the noise cancel function is executed or can be executed is displayed on the display section of the sound inputting and outputting apparatus  1 . 
         [0109]    Further, the control section  38 , reproduction section  39 , noise cancel signal production section  40  and synthesis section  41  described hereinabove with reference to  FIG. 13  may be formed by software or by hardware. 
         [0110]    While a preferred embodiment of the present invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.