Abstract:
A time-division multiplexing (TDM) exchange system enables the use of one pair of communication wires by a plurality of communication terminal devices at the same time to thereby reduce hardware and labor costs, and increase the economic effect of the exchange. The TDM exchange system includes a microprocessor, a customized integrated circuit (IC), and a plurality of branch interfaces.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a time-division multiplexing (TDM) exchange system, and more particularly to an exchange system that enables the use of one pair of communication wires by a plurality of communication terminal devices at the same time through a time-division multiplex communication technique, so that the connection of the communication terminal devices to the exchange is simplified, and a decreasing of quantity used in communication wire can be achieved.  
       BACKGROUND OF THE INVENTION  
       [0002]     In the modern society, various kinds of communication terminal devices are used by business offices, homes, and individuals. Among others, telephone has particularly become an important and requisite tool for the communication in daily life. The quantities of telephone sets being used as well as the communication equipment and wiring for providing communication via telephone are surprisingly high.  
         [0003]     To save the cost of communication, most places at where a large quantity of phones are needed, such as business offices, organizations, and governmental institutes, would normally install an exchange, to which multiple communication terminal devices, such as extensions, are connected for use by a large number of persons. In a conventional exchange, each extension is connected to a branch interface of the exchange via a pair of telephone wires. When the number of extensions is large, a large quantity of telephone wire is needed. Moreover, the conventional exchange must provide a branch interface for each of the extensions, resulting in high cost for the exchange equipment. In addition, a large manpower is needed to do and maintain the wiring between the exchange and the extensions.  
         [0004]     It is therefore tried by the inventor to develop a time-division multiplexing (TDM) exchange system to enable the use of one pair of communication wires by a plurality of communication terminal devices at the same time to reduce hardware and labor costs and increase the economic effect of the exchange.  
       SUMMARY OF THE INVENTION  
       [0005]     A primary object of the present invention is to provide a TDM exchange system that enables the supply of power and communication services to a plurality of communication terminal devices via only one pair of communication wires, so as to largely reduce the quantities of communication wire and exchange system components, and accordingly, the overall equipment cost of the exchange system.  
         [0006]     Another object of the present invention is to provide a TDM exchange system that enables each branch interface of the exchange to connect and provide services to multiple communication terminal devices at the same time to largely increase the economic effect of the exchange.  
         [0007]     A further object of the present invention is to provide a TDM exchange system that requires reduced numbers of wires and parts to largely simplify the wiring and maintenance of the whole communication network, and allows easy connection of new communication terminal devices to the exchange without increasing the manpower needed to maintain the exchange system.  
         [0008]     In a preferred embodiment of the present invention, the TDM exchange system includes a microprocessor for providing TDM communication services to a plurality of communication terminal devices; a customized integrated circuit (IC) for integrating the electronic circuits in the plurality of communication terminal devices into an integrated circuit; and a plurality of branch interfaces connected to the microprocessor via the customized IC. Each of the branch interfaces includes a transceiving circuit and a transformer, and is linked to at least one communication terminal device via only one pair of communication wires.  
         [0009]     According to the present invention, a plurality of communication terminal devices may be connected to one branch interface in parallel or in series. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein  
         [0011]      FIG. 1  is a block diagram showing the framework of the time-division multiplexing (TDM) exchange system according to the present invention;  
         [0012]    
       4 
     
         [0013]      FIG. 2  is a block diagram showing the structure of a branch interface included in the TDM exchange system of the present invention; and  
         [0014]      FIG. 3  is a block diagram showing the structure of an extension connected to the TDM exchange system of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     Please refer to  FIG. 1  that is a block diagram showing a framework of a time-division multiplexing (TDM) exchange system according to the present invention. As shown, in the framework of the present invention, there are included an exchange  10  and a plurality of communication terminal devices  20 . In the illustrated preferred embodiment, the communication terminal devices  20  are four various extensions  20   a - 20   d.  However, it is understood the communication terminal devices  20  may be any other devices for communication, and the number of the extensions is not limited to four but may be less or more.  
         [0016]     The exchange  10  includes a first microprocessor  102 , a first customized integrated circuit (IC)  104 , and a plurality of branch interfaces  106 .  
         [0017]     The first microprocessor  102  functions to provide time-division multiplex communication services, and controls all functions and flows of the exchange  10  via programs.  
         [0018]     The first customized IC  104  is located between and connected to the first microprocessor  102  and the plurality of branch interfaces  106  to integrate electronic circuits of the plurality of extensions  20  into an integrated circuit (IC).  
         [0019]     Please refer to  FIG. 2 . Each of the plurality of branch interfaces  106  includes a first transceiving circuit  206  and a first transformer  208 , and every branch interface  106  is connected via a pair of telephone wires to at least one extension  20  for communicating with the extension  20 . At least one extension  20  may be, for example, a first, a second, a third, and a fourth extension,  20   a,    20   b,    20   c,  and  20   d.  Wherein, the first transceiving circuit consists of a transistor adapted to conduct analog and digital signal conversion. The first transformer  208  is used to couple signals and isolate direct current (DC) voltage.  
         [0020]     Each of the branch interfaces  106  may be connected to a different number of extensions  20  for communication. The extensions  20  may be connected to the branch interface  106  either in parallel or in series.  
         [0021]     For example, one of the branch interfaces  106  is to connect to four extensions  20   a,    20   b,    20   c,    20   d,  and a distance between the four extensions  20   a - 20   d  and the exchange  10  is 200 meters. In this case, it needs to extend only one pair of telephone wires from the branch interface  106  to an area near the four extensions  20   a - d.  The four extensions  20   a - d  are then parallelly connected to the pair of telephone wires. That is, the length of the telephone wire required for connecting the exchange  10  to the four extensions  20   a - 20   d  is about 200 meters, and only one branch interface  106  is occupied. However, when the four extensions  20   a - 20   d  are connected to other conventional exchanges, total four branch interfaces  106  are needed to connect to one extension  20  each via one pair of telephone wires. That is, total 800 meters of telephone wire and total four branch interfaces  106  are required to connect the four extensions  20   a - 20   d  to the exchange. Therefore, with the time-division multiplexing exchange system of the present invention, total 600 meters of telephone line and three branch interfaces are saved, compared to the conventional exchange system.  
         [0022]     In another preferred example (not shown in the drawings), one of the branch interfaces  106  is to connect to 3 extensions  20   a - 20   c.  Wherein, a distance between a first extension A and an exchange  10  is 100 meters, a second extension B is 100 meters apart from the first extension A and 200 meters from the exchange  10 , and a third extension C is 100 meters away from the second extension B and 300 meters from the exchange  10 . In this case, it needs to extend only one pair of telephone wires from the branch interface  106  to the first extension A, and connect the second and the third extensions B &amp;C, to the first extension A in series. That is, the length of the telephone wire required for connecting the exchange  10  to the three extensions A-C is about 300 meters, and only one branch interface  106  is occupied. However, in the case of other types of conventional exchanges, total 600 meters of telephone wire and total three branch interfaces  106  are required to connect the three extensions A-C to the exchange. Therefore, with the time-division multiplexing exchange system of the present invention, total 300 meters of telephone wire and two branch interfaces are saved, compared to the conventional exchange system.  
         [0023]     The extensions  20  are preferably digital telephones having a structure shown in  FIG. 3 . Each of the extensions  20  has a second microprocessor  202 , a second customized IC  204 , a second transceiving circuit  206 , and a second transformer  208 . Wherein, the second microprocessor  202 , the second customized IC  204 , the second transceiving circuit  206 , and the second transformer  208  are structurally similar to the first microprocessor  102  and the first customized IC  104  in Ithe exchange  10 , and the first transceiving circuit and the first transformer in each branch interface  106 , except that the second microprocessor  202  controls the communication functions and flows of the extension  20  via programs, and the second customized IC  204  functions to connect the second microprocessor  202  to the second transceiving circuit  206 . The second microprocessor  202 , the second customized IC  204 , the second transceiving circuit  206 , and the second transformer  208  may be otherwise provided in a box, which is then externally connected to and between a general phone set and a general phone cord.  
         [0024]     The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.