Abstract:
The invention relates to a kind of multi-gateway communications system and switching control method, especially a system that is able to combine traditional Public Switched Telephone Network(PSTN) with Voice over Internet Protocol(VoIP). The multi-gateway communications system, connecting a user end with a caller end, can be utilized for verifying if a call is coming through Internet or POTS and automatically switching to enable the call receiver to answer the call. Moreover, the multi-gateway communications system provides with at least two switch components for the user end to choose if s/he wants to make a call through either Internet or POTS.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    (1) Field of the Invention  
           [0002]    The invention relates to a multi-gateway communications system with switching control method, especially a system that is applicable to at least two telephone communications technologies allowing users to select from any one of the telephone communications modes for use.  
           [0003]    (2) Description of the Prior Art  
           [0004]    The prevalence of Internet network at present time has made it a new trend in transferring a large amount of data or information through Internet. Moreover, the progress of semi-conductors and computer software/hardware designs enable data to be transformed from voice into a digital data packet, the technology for which is matured enough to enable the digital packet to be transferred to a call receiver end from Internet. Therefore, the convenience of Internet utilization for Data and Voice transfer apparently and largely decreases the payments of telephone communications, especially, international or long distance calls for enterprises or personal users.  
           [0005]    The existing Internet telephone system utilizes Internet voice packet transfer for achieving the purpose of telephone communications, however, the said system is unable to be combined with traditional plain old telephone service(POTS) network(as shown in FIG. 1). Thus, two sets of telephone devices have to be purchased if a user end has to make use of both systems at the same time(dialing or receiving), which situation rises some levels of inconveniences to general users, furthermore, the expenditure of purchasing two systems for use also one of the most concerns to general public.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of the foregoing drawbacks, the main object of the invention is to propose a multi-gateway communications system that is able to put a combination of POTS and Voice over Internet Protocol(VoIP) to use by two different switch components set on a telephone set(e.g., any two press buttons, etc.) to enable a user to make a call through either Internet or POTS. Moreover, the disclosed system is able to verify a call is dialed through Internet or POTS, then automatically switches the system status properly, so that calls from different telephone systems are able to be received by the same telephone (as shown in FIG. 2). In addition, the invention will automatically switch the telephone system to the status of the traditional Public Switched Telephone Network (PSTN) for normal operations of dialing or receiving telephones, when there is a power failure occurred.  
           [0007]    The detailed descriptions of the preferred embodiments are followed by the brief descriptions of the drawings below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a schematic diagram of respective the utilization of POTS and Internet communications;  
         [0009]    [0009]FIG. 2 is a systematic diagram of the co-existing communications systems in-between POTS and Internet;  
         [0010]    [0010]FIG. 3 is a systematic structure of the multi-gateway communications system according to the invention;  
         [0011]    [0011]FIG. 4 is a flowchart diagram of the call dialing process of the multi-gateway communications system of the invention;  
         [0012]    [0012]FIG. 5 is a flowchart diagram of the call receiving process of the multi-gateway communications system of the invention;  
         [0013]    [0013]FIG. 6 is a schematic diagram of the invention applying the multi-gateway communications system to a telephone set;  
         [0014]    [0014]FIG. 7 is a switching control device with pluralities of ports for connecting to PSTN line and Internet telephone systems applying the multi-gateway communications system of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    The invention focuses on a method of combining, switching and controlling in-between the systems of an external PSTN line and an Internet telephone, therefore, the system judgment and control and switch method will be further described hereinafter; whereas the matured and currently applied technologies of transforming voice signals into IP packets through Codec(Coder/Decoder), SLIC, DSP and CPU will not be further illustrated.  
         [0016]    [0016]FIG. 3 is the systematic structure of the multi-gateway communications system according to the invention. The said system comprises an input/output unit  11 , a detection unit  12 , a switch unit  13 , a SLIC unit  14  and a CPU &amp; DSP  15 . The units are further depicted as follows.  
         [0017]    The input/output unit  11  is to enable the multi-gateway communications system  10  to carry out the function of telephone communications for a caller end  20  or a user end  30 . The caller end  20  further comprises an external PSTN line  31  and an Internet communications line  32 . The input/output unit  11  can be a telephone handset.  
         [0018]    The detection unit  12  is to detect if the external PSTN line is connected, and if the input/output unit  11  is lifted by the user end. In the field of the detection of the external PSTN line, the invention mainly utilizes a bridge rectifier for detecting voltage of PSTN line through the Central Office (CO) end, in addition, and then utilizes a comparator and reverser for verifying if the line is connected and informing a CPU &amp; DSP  15  of the result for further actions. Besides, the invention employs an optical coupler to be serially connected to the telephone line, so that when the input/output unit  11  is lifted or hung up, different electric currents flow through the optical coupler to generate different outputted voltages for achieving the detection of lifting or hanging up the input/output unit  11 , the CPU &amp; DSP  15  will then be informed of the detected result for further operations.  
         [0019]    The switch unit  13  mainly connects the telephone line with the external PSTN line or a SLIC unit  14  by controlling Relay. The switch unit  13  integrates various statuses through the CPU &amp; DSP  15  to verify the subsequent control Relay and switch in between two networks, PSTN line or to SLIC line, connecting to the multi-gateway communications system  10 .  
         [0020]    The SLIC unit  14  is to transform voice signals into digital signals, which then are transferred to the DSP for further processing. The SLIC unit  14  is also a control interface to a telephone set for the tasks of impedance matching, required voltage control, vibration and receiving and verifying the detection of pressed button, etc.  
         [0021]    The CPU &amp; DSP  15  further comprises two units of CPU and DSP. Digital voice signals are received by DSP to be compressed for further processing by CPU, and then, are packed into Ethernet packets to be transferred to a call receiver end through Internet or LAN. When a call receiver unit is a system, the same principle is applicable to the system that voice packets are received by Ethernet for being decompressed into information by CPU and restored to analogue voice packets by DSP and the SLIC unit  14 . Another task of CPU is to send out the control command of switching lines and make appropriate switches based on the verifications of various situations, when a message is detected and received.  
         [0022]    The switch and verification method of the preceding system is further detailed as follows.  
         [0023]    [0023]FIG. 4 is the flowchart diagram of the call dialing process of the multi-gateway communications system of the invention. First, the flow verifies if there is an external PSTN line exists by the detection unit  12  through the multi-gateway communications system  10 (step  100 ). When the PSTN is disconnected, i.e., there is no an external line exists, the CPU &amp; DSP  15  controls the switch unit  13  and record the PSTN status (step  110 ), and directly switches the telephone set to the SLIC line. Without any external line existence, a user can only dial up through an Internet telephone. The multi-gateway communications system  10  then enters into a stand-by-for-dialing status and detects a switch component, which is selected by the user end  30  (step  130 ), for dialing through either a POTS or an Internet telephone by the input/output unit  11 .  
         [0024]    When the user end hangs up the telephone set, the invention automatically detects and informs CPU of the status, in addition, restores the system to the stand-by-for-dialing status (step  110 ) waiting for the next telephone call dialing or receiving.  
         [0025]    On the contrary, if there is any PSTN line being detected, the multi-gateway communications system  10  then increases a control condition to verify if the input/output unit  11  is used (step  120 ), if the telephone handset is lifted. If the input/output unit  11  is not under using, the multi-gateway communications system  10  enters into stand-by-for-dialing status and detects a switch component, which is chosen by the user end  30 (step  140 ), waiting for the user end  30  to dial through either a POTS or an Internet telephone.  
         [0026]    As shown in FIG. 5 that while the multi-gateway communications system  10  enters into a stand-by-for-dialing status waiting for receiving a call from the user end  30 , through either a POTS or an Internet telephone, if the caller end  20  dials the user end  30  through POTS using the input/output unit  11  (step A), the detection unit  12  detects the status of the caller end  20  (step  200 ). If the call is dialed through POTS, the user end  30  directly receives the call and ends up using the input/output unit  11  when the call is finished(step  210 ), the flow then goes back to the preceding status of (step  120 ). If the multi-gateway communications system  10  receives telephone communications signals from the caller end  20  through an Internet telephone, it then enters into Internet telephone mode and switches to the SLIC line through the switch unit  13  to enable the user end  30  to receive an Internet call(step  220 ). At last, the system goes back to the preceding status of (step  120 ) when telephone communications end up.  
         [0027]    Another situation is that assuming that both switch components are press buttons “0” and “#” on a telephone set, when the multi-gateway communications system  10  enters a stand-by-for-dialing status waiting for the user end  30  to choose a switch component (step  130  and  140 ) for dialing through either a POTS or an Internet telephone, the user end  30  can press either of the two press buttons as required and dial out through the input/output unit  11  through a POTS or an Internet telephone. Until the input/output unit  11  is hung up, the invention detects and informs CPU of the line status to restore the system to stand-by-for-dialing status of (step  120 ) waiting for the next telephone call dialing or receiving.  
         [0028]    Another situation is that the multi-gateway communications system  10  enters a stand-by-for-dialing status and detects an existed PSTN line, at the same time, the user end  30  presses the button “#” (set to dial Internet telephone), the SLIC unit  14  then checks and informs the CPU &amp; DSP  15 , which then further informs the switch unit  13  of the status to switch the multi-gateway communications system  10  to the SLIC line for the user end  30  to dial from Internet telephone (step  150 ). On the contrary, if the user end  30  presses the button “0”, the multi-gateway communications system  10  switches to PSTN line for the user end  30  to dial from POTS (step  160 ). Until the input/output unit  11  is finished being used, CPU is informed of the detected line status to restore the system to the stand-by-for-dialing status of (step  120 ) waiting for the next telephone call dialing or receiving.  
         [0029]    Another situation is that the multi-gateway communications system  10  does not detect any existed PSTN line, therefore, when the user end  30  presses the button “#”, s/he is able to dial out through an Internet telephone (step  170 ); whereas if s/he presses the button “0”, the multi-gateway communications system  10  then informs the user end  30  of failing to dial through an Internet telephone according to the PSTN status(step  180 ).  
         [0030]    The aforementioned switch components can be defined by the user end  30  as any component of the multi-gateway communications system interface, e.g., any two press buttons of a telephone set.  
         [0031]    In view of the foregoing descriptions, it is of course to be understood that the embodiment of the disclosed switching control method between the systems of POTS and Internet communications is described herein to enable a user end to dial from different telephone communications system through a multi-gateway communications system  10 , moreover, to save the expenditure of purchasing extra telephone set(s). In addition, the invention maintains the convenience of using POTS of a user. Besides, the invention is able to combine POTS with the said gateways making it a telephone set that can receive or dial a PSTN call through a POTS and an Internet telephone(as shown in FIG. 6), also a switching control device that enables to extend pluralities of PSTN lines with Ports and Internet telephone(as shown in FIG. 7).  
         [0032]    However, the said embodiment is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention are as set forth in the following claims.