Abstract:
An earphone jack handsfree includes an earphone jack signal line and a handsfree host. The earphone jack signal line has one end connecting to an earphone jack of a mobile phone and other end connecting to the handsfree host. The handsfree host includes at least a microphone, a speaker, a connection port, a control unit and a call detection unit. The handsfree thus formed can improve compatibility and reduce production and inventory costs.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to an earphone jack handsfree to improve compatibility of handsfrees and reduce production and inventory costs.  
         [0003]     2. Description of the Prior Art  
         [0004]     The conventional handsfree now on the market as the one shown in  FIG. 1  generally include a handsfree host  1  and a mating signal line  2 . The signal line  2  has a first connector  21  on one end to be connected to the handsfree host  1  and a second connector  22  on other end corresponding to a jack of a mobile phone. When a user changes a mobile phone, a new signal line  2  mating the new mobile phone is acquired but the old handsfree can still be used.  
         [0005]     While the conventional method mentioned above can solve the compatibility problem of the handsfree by replacing the signal line, the signal line has to receive required signals from the phone jack through a dedicated connector. The signals include sound signals, calling notice signals and the like. The mobile phones of the same brand might share a few common signal lines. But in most occasions one type of mobile phone has one mating and dedicated signal line. As there are a wide variety of mobile phones on the market, and they are obsolete very quickly, the conventional signal lines have disadvantages, notably: 
        1. The product life cycle of mobile phones is very short, developing dedicated signal lines with a special connector is more difficult and takes longer time. It could happen that after a new signal line is developed and introduced, the mating mobile phone has already been withdrawn from the market. Hence consumers cannot fully enjoy the benefit of handsfree when replacing the mobile phone, and have to procure a new vehicle handsfree. It is a waste of investment.     2. As the types and models of mobile phones are numerous, many different types of mating and dedicated signal lines also have to be developed and produced to meet market requirements. The costs of development and inventory of manufacturers are higher. Signal line vendors also have to stock many types of signal lines to meet market requirements. Once the mobile phones are withdrawn from the market, the stocked signal lines become useless. A huge loss occurs.        
 
       SUMMARY OF THE INVENTION  
       [0008]     The present invention aims to solve the aforesaid problems. The invention provides an earphone jack handsfree that includes an earphone jack signal line and a handfsree host. The earphone jack signal line has one end to be inserted into the earphone jack of a mobile phone and other end connecting to the handsfree host. The handsfree host includes at least a microphone, a speaker, a connection port, a control unit and a call detection unit.  
         [0009]     In one aspect, the call detection unit includes a wave detection circuit to detect electromagnetic wave while the mobile phone is in use for conversation to activate operation of the handsfree host.  
         [0010]     In another aspect, the call detection unit further includes an integration circuit to perform integration of sound signals output from the earphone jack of the mobile phone so that the sound signals are transformed from audio frequency to DC signals for comparison, thereby to determine whether the receiving signals are calling signals to avoid generating wrong actions.  
         [0011]     The invention can achieve the following effects: 
        1. The earphone jack handsfree can be developed easily and rapidly. Compared with the conventional handsfrees that are limited to dedicated signal line connectors, and communication signals and electric contacts of the mobile phone are restricted, the invention can be developed rapidly. It is progressive and novel. The invention can respond the fast changing mobile phones quickly so that the consumers having new types of mobile phones can acquire new types of signal line rapidly and continuously enjoy the benefits of vehicle handsfrees.     2. The earphone jack handsfree of the invention adopts earphone jack signal lines in fewer specifications. Each specification has the same circuit. Unlike the conventional handsfrees that have to use dedicated signal line connectors with different corresponding circuits to match different types of mobile phones, inventory of the manufacturers and vendors can be reduced. The compatibility of the handsfree increases. The concern of idle or overstock caused by obsolete mobile phones is reduced. Production and inventory costs are lower.     3. The earphone jack handsfree of the invention uses the earphone jack of mobile phones of a universal specification as the connection end. A few specifications can be adapted to a wide variety of mobile phones and handsfree hosts. The incompatibility problem when the mobile phone is changed can be prevented.        
 
         [0015]     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a schematic view of a conventional handsfree.  
         [0017]      FIG. 2  is a schematic view of the earphone jack signal line of the invention.  
         [0018]      FIG. 3  is a schematic view of an embodiment of the invention.  
         [0019]      FIG. 4  is a schematic view of another embodiment of the invention.  
         [0020]      FIG. 5  is another schematic view of another embodiment of the invention.  
         [0021]      FIG. 6  is a circuit block diagram of an echo cancellation unit of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     Referring to  FIGS. 2 and 3 , the earphone jack handsfree according to the invention includes an earphone jack signal line  3  and a handsfree host  4 .  
         [0023]     The earphone jack signal line  3  has a conductive wire  30  with a first connector  31  on one end and a second connector  32  on other end. The earphone jack signal line  3  includes at least an earphone circuit  301  and a mike circuit  302 . The first connector  31  is to be inserted into an earphone jack of a mobile phone P. The second connector  32  is to be connected to the handsfree host  4 . Through the earphone circuit  301  and mike circuit  302 , output or input of sound signals in the earphone jack of the mobile phone P can be transmitted.  
         [0024]     The handsfree host  4  includes at least a microphone  41 , a speaker  42 , a control unit  43 , a connection port  44  and a call detection unit  45 .  
         [0025]     The microphone  41  receives sound signals of users.  
         [0026]     The speaker  42  outputs the sound signals of a caller or mobile phone P.  
         [0027]     The control unit  43  controls operations of various elements in the handsfree host  4 .  
         [0028]     The connection port  44  is connected to the second connector  32  of the earphone jack signal line  3 .  
         [0029]     The call detection unit  45  includes a wave detection circuit to detect electromagnetic signals while the mobile phone is in use for conversation to activate operation of the control unit  43 .  
         [0030]     By means of the elements set forth above, when in use, the first connector  31  is connected to the earphone jack of the mobile phone P, and the second connector  32  is connected to the connection port  44  of the handsfree host  4 . When there is a call to the mobile phone P, the call detection unit  45  gets electromagnetic signals from the base station that communicate with the mobile phone P, and activates the operation of the control unit  43  so that the handsfree host  4  starts operation. Hence the sound transmitted to the mobile phone P is sent through the earphone jack circuit  301  and mike circuit  302  of the earphone jack signal line  3  to the handsfree host  4 , and broadcast through the microphone  42 . Meanwhile, user&#39;s sound also can be transmitted through the microphone  41  to the transceiver of the caller to do conversation.  
         [0031]     Refer to  FIG. 4  for a second embodiment of the invention. To prevent the handsfree host  4 ′ from operating in the wrong way caused by signal exchanged between the base stations of telecommunication providers while the mobile phone P is moved, the call detection unit  45 ′ further has an integration circuit  451 ′ which is coupled in parallel with the earphone circuit  301 . Thereby the sound signal output from the earphone jack of the mobile phone P is integrated, and the integrated waveform is transformed from an audio frequency to a DC signal. Hence the sound exceeding a selected ranged can be set to be integrated and treated as the calling signal. Through the integration circuit  451 ′ and the call detection unit  45 ′, the calling signal can be determined correctly to activate operation of the handsfree host  4 ′. Hence the calling sound of the mobile phone P can be transmitted through the earphone jack of the mobile phone P, the earphone circuit  301  and the mike circuit  302  to the handsfee host  4 ′, and wrong operation can be prevented.  
         [0032]     Refer to  FIGS. 5 and 6  for a third embodiment of the invention. To prevent echo sound from occurring to the handsfree, the handsfree host  4 ″ further has an echo cancellation unit  46 ″ which includes a first digital processing circuit  461 ″ and a second digital processing circuit  462 ″. The first digital processing circuit  461 ″ is located on the mike circuit  302  and connected to the earphone circuit  301  to compare the digitized sound information and determine the echo sound and the sound of car drivers transmitting from the microphone. The echo sound is eliminated and the desired sound is transmitted through the mike circuit  302  to the mobile phone P. The mobile phone P transmits the sound signal to the remote user so that there is no echo sound on the remote side. The second digital processing circuit  462 ″ aims to cancel line echo (or side tone), namely the commonly called input echo. It mainly caused by the mike sound entering from the mike circuit  302  to the mobile phone P, and the mobile phone P sending the sound signal through the earphone circuit  301  to the speaker  42 ″. Hence the second digital processing circuit  462 ″ is used to cancel line echo. It is located on the earphone circuit  301  and connected to the mike circuit  302 . The sound signal transmitted from the microphone is digitized and compared with the sound signal transmitted from the earphone circuit  301 , and is differentiated and separated to get the real signal of the earphone circuit  301  for sending to the speaker  42 ″. The signal thus generated is the pure calling signal of the mobile phone.  
         [0033]     In summary, the invention uses the earphone jack of the mobile phone that is rarely changed to function as the connection port of the handsfree host and the mobile phone. Only a minimum number of earphone jack signal line specifications are needed to connect various types of mobile phones to the handsfree host.  
         [0034]     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiment thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.