Abstract:
The present invention is a circuit that is set in a communication apparatus. The circuit is co-operated with a button of an audio receiving/transmitting device for triggering an on-hook or off-hook function when the communication apparatus receives an incoming call. The button is normally closed. The on-hook and off-hook functions are triggered by a triggering signal which is higher than a threshold value. Thus, the present invention doesn&#39;t execute the on-hook or off-hook function by an on/off button set in the communication apparatus but directly execute the button set in the audio receiving/transmitting device, which improved the convenience of the communication apparatus.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a circuit for triggering an on-hook and off-hook function of a communication apparatus.  
           [0003]    2. Description of the Prior Art  
           [0004]    Mobile phones are the most universal mobile communication apparatus currently, but in some situations, users cannot conveniently use mobile phones. For example, when a user is riding a motorbike or driving a car, and there is an incoming call, the user may be diverting additional attention to communicate on the phone, and a traffic accident often happens under that situation; therefore, it is very dangerous.  
           [0005]    In order to avoid that situation, each company has launched its own audio receiving/transmitting device for their mobile communication apparatus, such as the hands-free phone. The device lets the users communicate without having to hold the mobile phones, thus freeing their hands to perform other functions. However, the conventional audio receiving/transmitting device still has a disadvantage. When the mobile phones receives an incoming call, the user still needs to push button on the mobile phones for answering the phone; then, the user can talk by the mobile phones. When ending the phone call, the user must also need to push buttons on mobile phones to hang up; therefore, the conventional mobile phones is still not convenient to use.  
         SUMMARY OF THE INVENTION  
         [0006]    The objective of the invention is to provide a circuit that is suitable for the audio receiving/transmitting device of the communication apparatus for solving the problem of the prior art.  
           [0007]    The present invention relates to a circuit; the circuit is set in a communication apparatus, and it co-operates with a button of an audio receiving/transmitting device for triggering the on-hook function by pressing the button while the communication apparatus receives an incoming call, or triggering the off-hook function while ending the communication. The switch of the button is normally closed. The communication apparatus comprises an audio-signal receiving port, a bias source, and a detecting-signal input port. When the detecting signal value inputted in the detecting-signal input port is higher than a threshold value, the communication apparatus is triggered. The method of triggering is determined by the processor of the communication apparatus, and it can be for the on-hook or off-hook function.  
           [0008]    The circuit comprises a connecting device, a first signal line, a second signal line, and a detecting device. The audio receiving/transmitting device electrically and detachably connects to the connecting device. The connecting device comprises an audio-signal input end, and the first signal line connects the audio-signal receiving port and the audio-signal input end. The second signal line connects the bias source and the first signal line. The detecting device electrically connects to the first signal line and the detecting-signal input port respectively, wherein a first connecting point is defined in the place where the detecting device electrically connects to the first signal line. The detecting device is used for detecting a detecting signal of a voltage value of the first connecting point and outputting a detecting-signal value of the detecting signal to the detecting-signal input port; the detecting signal value is a converted value.  
           [0009]    When the audio receiving/transmitting device is electrically connected to the connecting device, the communication apparatus receives the incoming call, and the button is pressed, the circuit between the audio-signal input end of the connecting device and the audio receiving/transmitting device is temporarily broken. The detecting device detects that the detecting-signal value is higher than a threshold value, and then the on-hook function of the communication apparatus is triggered.  
           [0010]    When the audio receiving/transmitting device is used in the communication apparatus and is communicating normally, and the button is pressed again, the circuit between the audio-signal input end of the connecting device and the audio receiving/transmitting device is temporarily broken again. The detecting device detects that the detecting-signal value at the first connecting point is higher than a threshold value; then, the off-hook function of the communication apparatus is triggered.  
           [0011]    Therefore, by controlling the button appended in the audio receiving/transmitting device, the present invention can answer the incoming call and hang up the phone when the communication ends. Thus, it is unnecessary for the user to answer or hang up a phone call by using the button on the communication apparatus. The present invention avoids the disadvantage of the prior art.  
           [0012]    The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE APPENDED DRAWINGS  
       [0013]    [0013]FIG. 1 is an external view of a communication apparatus and an audio receiving/transmitting device according to the present invention.  
         [0014]    [0014]FIG. 2 is a schematic diagram of the circuit according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    Referring to FIG. 1, FIG. 1 is an external view of a communication apparatus  10  and an audio receiving/transmitting device  12  according to the present invention; FIG. 2 is a schematic diagram of the circuit  20  according to the present invention. The audio receiving/transmitting device  12  comprises a button  14 , a connecting head  16 , and a transmitting line  17 . In FIG. 1, the arrowhead represents that the audio receiving/transmitting device  12  connects to the communication apparatus  10  by the connecting head  16 . The connecting head  16  connects to the transmitting line  17 , and the transmitting line  17  comprises an audio-signal input line  18  and an audio-signal output line  19  for transmitting the audio input signal. The button  14  is set on the audio-signal input line  18 .  
         [0016]    The circuit  20  co-operates with a button  14  of an audio receiving/transmitting device  12  for triggering the on-hook or off-hook function while the communication apparatus  10  is receiving an incoming call or ending the communication. The button  14  is normally closed; that means the audio-signal input line  18  and the circuit  20  remains connected under normal condition.  
         [0017]    [0017]FIG. 2 only shows a part of the elements of the audio receiving/transmitting device  12 ; the audio receiving/transmitting device  12  comprises the connecting head  16 , the transmitting line  17 , and the button  14 , wherein the transmitting line  17  comprises the audio-signal input line  18  and the audio-signal output line  19 . FIG. 2 also shows a part of the elements of the communication apparatus  10  only; the communication apparatus  10  comprises an audio-signal receiving port  32 , a bias source  34 , a detecting-signal input port  36 , an audio-signal output port  38 , and a processor  40 . The circuit  20  of the present invention comprises a connecting device  22 , and the audio receiving/transmitting device  12  electrically and detachably connects to the connecting device  22  by the connecting head  16 . The connecting device  22  comprises an audio-signal input end  23  and an audio-signal output end. The circuit  20  further comprises a first signal line  24  for connecting the audio-signal receiving port  32  and the audio-signal input end  23 , a second signal line  26  for connecting the bias source  34  and the first signal line  24 , and a third signal line  29  for connecting the audio-signal output end  25  and the audio-signal output port  38 .  
         [0018]    Moreover, the circuit  20  comprises a detecting device  28 ; the detecting device can be an analog-to-digital converter. The detecting device comprises a detecting input end  42  and a detecting output end  44 . The detecting device  28  electrically connects to the first signal line  24  by the detecting input end  42 , and the detecting-signal input port  36  by the detecting output end  44 . The detecting-signal input port  36  is a signal input port of the processor  40 ; the processor  40  processes the inner signal-control functions of the communication apparatus. The place where the detecting device  28  electrically connects to the first signal line  24  is defined as the first connecting point P 1 . The second signal line  26  comprises a bias resistance  27  which connects to the second signal line  26  in series connection. The place where the second signal line  26  connects to the first signal line  24  is defined as a second connecting point P 2 .  
         [0019]    As shown in FIG. 2, when the communication apparatus  10  receives an incoming call, the audio-signal receiving port  32  and the audio-signal output port  38  prepare to start transmitting or receiving the audio input signal of the audio receiving/transmitting device  12 . The bias source outputs a bias voltage V b , which is higher than a threshold voltage V t , to the second signal line  26 . When the detecting device  28  is an analog-to-digital converter, the detecting device  28  detects a detecting voltage V d  at the first connecting point P 1  and digitizes the voltage value to transmit to the processor  40  by the detecting-signal input port  36 .  
         [0020]    As shown in FIG. 2, when the audio receiving/transmitting device  12  electrically connects to the connecting device  22 , and the communication apparatus  10  receives the incoming call, because the button  14  is normally closed, the whole circuit  20  remains connected. At the moment, the voltage detected by the detecting device  28  is smaller than the bias voltage V b  and the threshold voltage V t , wherein the threshold voltage is about 1.8V; therefore, when the detecting device  28  converts the present voltage to the detecting signal value and outputs to the processor  40 , the processor  40  does not activate any function. However, when the button  14  is pressed, the circuit between the audio-signal input end of the connecting device  22  and the audio receiving/transmitting device  12  is temporarily broken. In FIG. 2, the arrowhead represents that the button is pressed, and the switch that originally remains closed is temporarily open and forms a broken circuit. In this situation, the voltage at the first connecting point P 1  is approximately equal to the bias voltage V b , wherein the bias voltage is larger than 1.8V. Because the bias voltage V b  is higher than the threshold voltage V t , when the detecting device  28  converts the present voltage to a detecting signal value and transmits it in the digital-signal form to the processor  40  by the detecting-signal input port  36 , the processor  40  would compare the detecting voltage V d  with the threshold voltage V t  stored in the processor  40 . If V d  is higher than the threshold voltage V t , the processor  40  activates the on-hook function of the communication apparatus  10 . After the on-hook function of the communication apparatus  10  is activated, the users can communicate by the audio receiving/transmitting device  12 .  
         [0021]    As shown in FIG. 2, if the user wants to end the communication, the user only needs to press the button  14  again. As previously described, the circuit between the audio-signal input end  23  of the connecting device  22  and the audio receiving/transmitting device  12  is temporarily broken again; that further causes the detecting voltage V d  to be higher than the threshold voltage V t , to trigger the off-hook function of the communication apparatus  10 . After the off-hook function of the communication apparatus  10  is triggered, the audio communication is ended, and each device connected to the circuit  20  is also shut down.  
         [0022]    According to the above description, by controlling the button  14  appended in the audio receiving/transmitting device  12 , the present invention can answer an incoming call and hang up the phone when the communication ends. Therefore, it is unnecessary for the user to answer or hang up a phone call through the communication apparatus; the present invention can avoid the disadvantage of the prior art efficiently and improve the efficiency of the audio receiving/transmitting device  12 .  
         [0023]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.