Abstract:
A method for transmitting audio data between a computer and a GPRS card. The computer is connected to the GPRS card through corresponding connectors. The method includes after the computer receives an audio signal, transforming the audio signal into a digital signal, and packeting the digital signal into a plurality of audio units, then transmitting the plurality of audio units to the GPRS card through the connectors. Finally, the plurality of audio units are transformed to become the original digital signal, and the digital signal is transformed to become the original audio signal.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a voice data transmission method, and more particularly, to a method of transmitting voice information between a computer system and a General Packet Radio Services (GPRS) card.  
           [0003]    2. Description of the Prior Art  
           [0004]    People often use international dialing to get in touch with friends and family who are out of the country, but a price rate of international phone calls is very expensive, becoming a burden. When a caller is an international business, frequently contacting overseas clients, these charges can become a substantial financial expenditure. With a daily growth in expansion of the Internet, designers have already integrated the Internet with telephone communication to create Internet telephone. Internet telephone users can use a computer microphone and speakers to record and play voice information. Through a sound card in the computer, the recorded information can be converted to digital data and sent to another user. Similarly, the other user can send information back to the original user, who then plays the sound from their computer. In this way, people can use the Internet to accomplish telephone communication. As the cost of the Internet telephone service is very low, users can talk for long periods of time, without worrying about an expensive phone bill. Additionally, because the voice information is processed by the sound card of the computer, the sound quality is very pure.  
           [0005]    However, the Internet telephone of the present is mostly limited to sending voice over a wired Internet, and does not have an effective wireless service. This makes it so the user does not have “anytime, anywhere” service when employing the Internet telephone.  
         SUMMARY OF INVENTION  
         [0006]    Therefore, it is an objective of the claimed invention to provide a method of achieving wireless Internet telephone communication. Particularly, a method of allowing voice signals to be passed between a computer and a GPRS card achieves wireless Internet phone capabilities, and solves the problems faced by the prior art.  
           [0007]    The claimed invention method waits for the computer system to receive voice sounds, converts the voice sounds to a voice packet, sends the voice packet over the USB to the GPRS card, and uses the GPRS card to convert the voice packet to a voice signal. The voice signal is then transmitted away wirelessly.  
           [0008]    It is an advantage of the claimed invention method that it allows users to perform telephone communication over a wireless network.  
           [0009]    These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]    [0010]FIG. 1 is a block diagram of a computer system according to the present invention.  
         [0011]    [0011]FIG. 2 is a block diagram of a GPRS card connected to the computer system of FIG. 1.  
         [0012]    [0012]FIG. 3 is an execution flow chart of the computer system of FIG. 1.  
         [0013]    [0013]FIG. 4 is an execution flow chart of the GPRS of FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0014]    General Packet Radio Services (GPRS) is a high-speed, broadband, wireless mobile network that was developed by the European Telecommunications Standards Institute, which supports transmission of one 100 KB data packet per second, and is characterized by quick access and high-speed transmissions. Because GPRS has these high-speed, wireless transmission capabilities, the present invention uses a GPRS card in connection with a computer system to send voice information over a wireless network, and perform wireless Internet phone service.  
         [0015]    Please refer to FIG. 1 and FIG. 2. FIG. 1 is a block diagram of a computer system  10  of the present invention method. FIG. 2 is a block diagram of a GPRS card  30  of the present invention method. The computer system  10  comprises a microphone  12 , a speaker  14 , a sound card  16 , a first CPU  18 , and a USB port  20 . The microphone  12  is used to receive voice signals from a user, and the speaker  14  is used to play voice signals. The sound card  16  is connected between the first CPU  18  and the microphone  12  (or the speaker  14 ). The first CPU  18  is connected between the sound card  12  and the USB port  20 . Additionally, the GPRS card  30  comprises an antenna  32 , a Global System for Mobile Communications (GSM) module  34 , a compression/decompression module (CODEC)  36 , a second CPU  38  and a USB port  40 . The antenna  32  is used to receive and transmit wireless signals. The GSM module  34  is used to process wireless signals. The CODEC  36  is connected between the GSM module  34  and the second CPU  38 . The second CPU  38  is connected between the CODEC  36  and the USB port  40 .  
         [0016]    To use the wireless Internet phone, the user must first make sure that the GPRS card  30  and the computer system  10  are connected by their respective USB ports  20 ,  40 . Then, the user can open GPRS software in the computer system  10 . This allows the user to use the computer system  10  to call out or receive phone calls. At this time, if the user wishes to talk with a distant friend, the user, after connection, can use the microphone  12  of the computer system  10  to input their own voice signal, and the signal is sent to the sound card  16  of the computer system  10 . After the sound card  16  receives the signal, the sound card  16  converts the signal to a digital voice signal with pulse-code modulation (PCM). This digital signal is sent ahead to the first CPU  18  of the computer system  10 , which uses a special AT command format to package the digital voice signal into a complex voice packet, which is sent to the second CPU  38  of the GPRS card  30  through the USB ports  20 , 40 . The second CPU  38  changes the received packet back into a digital signal, and sends the signal to the CODEC  36 , which then turns the digital signal back into a voice signal. The voice signal is then sent to the GSM module  34 , which processes the signal, and wirelessly sends it from the antenna  32 . In this way, the distant friend can use wireless technology to receive the voice signal of the user.  
         [0017]    Similarly, if the distant friend uses wireless technology to send a voice signal, the user can use the antenna  32  of the GPRS card  30  to receive the voice signal. The signal, after being processed by the GSM module  34 , is sent to the CODEC  36 , which digitizes the signal, and sends it to the second CPU  38 . The second CPU  38  packets the digital signal into a complex packet, which is sent through the USB ports  20 , 40  to the first CPU  18  of the computer system  10 . The first CPU  18  converts the packet to a PCM digital signal and sends it to the sound card  16 . The sound card  16  converts the PCM signal to a voice signal and plays the voice signal over the speakers  14  that are installed in the computer system  10 . In this way, the user can receive voice signals from the distant friend.  
         [0018]    Please refer to FIG. 3 and FIG. 4. FIG. 3 is an execution flow chart of the computer  10  of the present invention method. FIG. 4 is an execution flow chart of the GPRS card  30  of the present invention method. The present invention method can be split into two parts: the execution flow of the computer system  10 , and the execution flow of the GPRS card  30 . The steps are as follows:  
         [0019]    Execution of the computer system  10 :  
         [0020]    Step  100 :  
         [0021]    User connects the computer system  10  and the GPRS card  30  through the USB ports  20 , 40 , and opens software of the GPRS card  30  that is in the computer  10 . The software enters a waiting state. Go to step  110 .Step  110 : User dials or receives a call. Go to step  120 ;  
         [0022]    Step  120 :  
         [0023]    The computer system  10  sends a signal to the GPRS card  30  to tell the GPRS card  30  that the user has already started telephone communication. Go to step  130 ;  
         [0024]    Step  130 :  
         [0025]    Determine whether or not the user has finished telephone communication. If finished, go to step  140 , else go to step  150 ;  
         [0026]    Step  140 :  
         [0027]    The computer system  10  sends a signal to the GPRS card  30  telling the GPRS card  30  that the user has finished telephone communication. Return to step  100 ;  
         [0028]    Step  150 :  
         [0029]    Determine whether or not the user is using the microphone  12  of the computer system  10  to input voice signals. If not, go to step  160 , else go to step  190 ;  
         [0030]    Step  160 :  
         [0031]    Send the voice signal inputted by the user to the sound card  16 , use the sound card  16  to convert the voice signal to a PCM signal, and send the PCM signal to the first CPU  18 . Go to step  170 ;  
         [0032]    Step  170 :  
         [0033]    After the first CPU  18  receives the PCM signal, use a special AT command format to packet the digital signal into a complex packet. Go to step  180 ;  
         [0034]    Step  180 :  
         [0035]    Send the packet through the USB ports  20 ,  40  to the GPRS card  30  to perform further processing. Return to step  130 ;  
         [0036]    Step  190 :  
         [0037]    Determine whether or not a voice packet has been received from the GPRS card  30 . If so, go to step  200 , else return to step  130 ;  
         [0038]    Step  200 :  
         [0039]    Send the voice packet received from the GPRS card  30  to the first CPU  18 . Use the first CPU  18  to convert the received voice packet to a PCM signal, and send the PCM signal to the sound card  16 . Go to step  210 ;  
         [0040]    Step  210 : After the sound card  16  receives the PCM signal, use the sound card  16  to convert the PCM signal to a voice signal, and play the voice signal over the speakers  14 . Return to step  130 .  
         [0041]    Execution of the GPRS card  30 :  
         [0042]    Step  300 :  
         [0043]    GPRS card  30  enters a wireless Internet telephone waiting state. Go to step  310 ;  
         [0044]    Step  310 :  
         [0045]    Use a signal received from the computer system  10  to tell the user that telephone communication has begun. Go to step  320 ;  
         [0046]    step  320 :Start the CODEC  36 . Go to step  330 ;  
         [0047]    Step  330 :  
         [0048]    Determine whether or not a signal has been received from the computer system  10  indicating that the user has ended telephone communication. If so, go to step  340 . Else, go to step  350 ;  
         [0049]    Step  340 :  
         [0050]    GPRS card  30  received a terminate telephone communications signal from the computer system  10 . Turn off the CODEC  36 . Return to step  300 ;  
         [0051]    Step  350 :  
         [0052]    Determine whether or not the GSM module  34  is receiving voice signals over the antenna  32 . If so, go to step  360 . Else, go to step  390 ;  
         [0053]    Step  360 :  
         [0054]    Send the voice signal from the GSM module  34  to the CODEC  36 . Use the CODEC  36  to convert the voice signal to a digital signal, and send the digital signal from the CODEC  36  to the second CPU  38 . Go to step  370 ;  
         [0055]    Step  370 :  
         [0056]    After the second CPU  38  receives the signal, use the second CPU  38  to convert the digital signal to a complex voice packet. Go to step  380 ;  
         [0057]    Step  380 :  
         [0058]    Send the complex voice packet to the computer system  10  through the USB ports  20 ,  40 . Return to step  330 ;  
         [0059]    Step  390 :  
         [0060]    Determine whether or not the second CPU  38  has received a voice packet from the computer system  10 . If so, go to step  400 . Else, return to step  330 ;  
         [0061]    Step  400 :  
         [0062]    Use the second CPU  38  to convert the voice packet received from the computer system  10  to a digital signal, and send the digital signal from the second CPU  38  to the CODEC  36 . Go to step  410 ;  
         [0063]    Step  410 : Use the CODEC  36  to convert the digital signal to a voice signal, and send the voice signal to the GSM module  34 . Use the GSM module  34  to send the voice signal out over the antenna  32 . Return to step  330 .  
         [0064]    Compared to the prior art, the present invention method uses the computer system  10  connected with the GPRS card  30  to achieve wireless Internet telephone communication. Thus, the user not only enjoys the low cost of Internet telephone, but can also benefit from the convenience of wireless network transmission. Additionally, GPRS provides high-speed, broadband wireless access, so the user can freely communicate with distant friends, not having to worry about Internet traffic or disconnections.  
         [0065]    Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.