Abstract:
A transfer method of a push-button signal includes the steps of detecting a push-button signal created by an end user terminal during a state in which the end user terminal is connected to a remote service system by an exchange via a network, by using a push-button signal receiver, encoding the push-button signal detected by the push-button signal receiver to a produce a push-button transfer signal by using the push-button signal receiver, and transmitting the push-button transfer signal to the service system from the exchange to the service system via a signal line of the network.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to telecommunication systems and more particularly to a transfer of push-button signals from a terminal to a service system via an exchange. 
     Conventionally, it is practiced to provide various services such as reservation of air tickets, collection of questionnaires, and the like, by transferring push-button signals created by a push-button telephone set or a personal computer having an equivalent function to an appropriate service system. 
     FIG. 1 shows the construction of a conventional transfer system of push-button signals. 
     Referring to FIG. 1, an exchange  10  carries out a switching of a network (NW)  11  and accommodates therein a line to an end user terminal  12 , which may be a push-button telephone or a personal computer having an equivalent function. The exchange  10  further includes a push-button signal receiver (PBR)  14  for detecting push-button signals supplied from the end user terminal  12  to the exchange  10 , wherein the push-button signal receiver  14  further converts the detected push-button signals to a corresponding code. As a result of the foregoing conversion, the address (telephone number) of the destination terminal is recognized when a call is issued by the end user terminal  12 . 
     Further, it should be noted that the network  11  is connected to a service system (SS)  16  that provides various services such as reservation of air tickets or collection of questionnaires. The network  11  may use a common-line transmission process in which various monitoring and control signals are transmitted through a common signal line  18 . For the transmission of an audio signal, an audio-channel  20  is provided. It should be noted that the exchange  10  and the service system  16  are connected to the audio-channel  20  via trunks (TRK)  21  and  22 . Further, the service system  16  also includes a push-button signal receiver (PBR)  24 . 
     In operation, a push-button signal issued by the user at the terminal  12  during a state in which there is a circuit connection between the end user terminal  12  and the service system  16 , is transferred to the service system  16  from the exchange  10  to the audio-channel  20 , wherein the push-button signal receiver  24  of the service system  16  detects the push-button signal and converts the same into a corresponding code. 
     In such a conventional system, in which the exchange  10  accommodates therein the line to the end user terminal  12 , it is essential that the exchange  10  has the push-button signal receiver  14  for detecting the destination address supplied from the end user terminal  12  at the time of setting up a call in the form of push-button signals and for converting the push-button signals to a corresponding code. On the other hand, the conventional system of FIG. 1, in which the push-button signals are transmitted through the audio-channel  20 , has required the service system  16  to have the push-button signal receiver  24  also in addition to the push-button signal receiver  14 , for detecting the push-button signals transmitted through the audio-channel  20  and for converting the same to a corresponding code. Thereby, there has been a problem in the conventional system of FIG. 1 that the cost of investment is excessive. 
     Further, in the conventional system of FIG. 1, there has been a problem in that the push-button signal, supplied by the end user at the terminal  12  and transmitted through the audio-channel  20 , may experience attenuation as it is propagated through the audio-channel  20  for a long distance. Thereby, there is a substantial risk hat the transmittance of the push-button signals is impaired and the chance of erroneous reception at the service system  16  is increased. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a general object of the present invention to provide a novel and useful transfer method of push-button signals wherein the foregoing problems are eliminated. 
     Another and more specific object of the present invention is to provide a transfer method of push-button signals to a service system, wherein the need of providing a push-button signal receiver in the service system is eliminated and wherein the risk of erroneous reception of the push-button signals is reduced substantially. 
     Another object of the present invention is to provide a transfer method of a push-button signal in an exchange connected to a network, said exchange accommodating therein a line to a terminal, said exchange including a push-button signal receiver for detecting a push-button signal created by said end terminal and for converting said push-button signal to a corresponding code, said method comprising the steps of: 
     detecting a push-button signal created by said terminal, during a state in which said exchange connects said terminal to a remote service system via said network, by using said push-button signal receiver; 
     encoding said push-button signal detected by said push-button signal receiver to a produce a push-button transfer signal corresponding to said push-button signal by using said push-button signal receiver; and 
     transmitting said push-button transfer signal to said service system from said exchange to said service system via a signal line of said network. 
     According to the present invention, it is no longer necessary to provide additional push-button signal receiver in the remote service system and the cost of the service system is reduced, without increasing the cost of the exchange. As the push-button signals are transmitted from the exchange to the remote service system through the signal line of the network, not through the audio-channel, in the form of encoded push-button transfer signals, the problem of signal decay of the transmitted push-button transfer signal is eliminated and a reliable transfer is achieved for the information of the original push-button signals. It should be noted that the push-button signal receiver of the exchange is the same push-button signal receiver used for setting up a circuit between the terminal and the service system. 
     Other objects and further features of the present invention will become apparent from the following detailed description when read in conjunction with the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram showing the construction of a conventional telecommunication system; 
     FIG. 2 is a diagram showing the construction of a telecommunication system of the present invention; 
     FIG. 3 is a diagram showing a part of the system of FIG. 2 in detail; 
     FIG. 4 is a flowchart showing an operation of an exchange included in the system of FIG. 2 according to a first embodiment of the present invention; 
     FIG. 5 is a flowchart showing an operation of an exchange included in the system of FIG. 2 according to a second embodiment of the present invention; 
     FIG. 6 is a diagram explaining an audio-channel path inside the exchange of FIG. 2; 
     FIG. 7 is another diagram explaining a disconnection of the audio-channel path in the exchange of FIG. 2 according to the present invention; 
     FIG. 8 is diagram showing a signal format of an encoded push-button transfer signal used in the present invention; 
     FIG. 9 is a diagram showing a signal format of a PBR connection/disconnection signal used in the present invention; 
     FIG. 10 is a diagram showing another signal format of an encoded push-button transfer signal used in the present invention; 
     FIG. 11 is a diagram showing another signal format of a PBR connection/disconnection signal; 
     FIG. 12 is a flowchart showing an operation conducted by a service system included in the system of FIG. 2; 
     FIG. 13 is a flowchart showing another operation conducted by the service system of FIG. 2; and 
     FIG. 14 is a flowchart showing an operation conducted by a relaying exchange included in network of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 shows the construction of a telecommunication system to which the present invention is used. 
     Referring to FIG. 2, the telecommunication system includes an exchange  30  for switching a public network (NW)  31  and accommodates therein a line extending to an end user terminal  32 , which may be a push-button telephone or a personal computer having the same function. The exchange  30  includes a push-button signal receiver (PBR)  34 , wherein the PBR  34  is used at the time of setting up a circuit between the terminal  32  and a destination terminal so as to detect the push-button signals supplied from the terminal  32  to the exchange  30  for designation of the destination terminal. Thereby, the PBR  34  further encodes the push-button signals thus supplied and converts the same to a code corresponding to the push-button signals. The exchange  30  recognizes the destination address based on the code thus obtained by the PBR  34 . 
     Further, it should be noted that the construction of FIG. 2 further includes a service system (SS)  36  connected to the public network  31 . The public network  31  uses the common signal line process for transmission of signals, in which a common signal line  38  is used for monitoring and control purposes while the audio signal is transmitted through an audio-channel  40 . Each of the exchange  30  and the service system  36  is connected to the audio-channel  40  via a trunk (TRK)  41  or a trunk (TRK)  42 . 
     FIG. 3 shows the construction of the service system  36 . 
     Referring to FIG. 3, the service system  36  includes a service switching point (SSP)  44  and a service control point (SCP)  46 , wherein the service switching point  44  is connected to the audio-channel  40  of the public network  31  via the trunk  42  and further to the common signal line  38  of the public network  31  for switching connection similarly to the exchange  30  between the public network  31  and the service control point  46 . 
     The service control point  46  provides various services such as reservation of air tickets, collection of questionnaires, and the like and is connected to the end user terminal  32  via the service switching point  44  and the public network  31 . 
     FIG. 4 shows the operation of the exchange  30  for processing the push-button signals according to a first embodiment of the present invention in the form of a flowchart. 
     Referring to FIG. 4, the processing is conducted for each circuit connection in the state that the circuit connection is established between the end user terminal  32  and the service system  36  and is started from a step S 10  in which a discrimination is made whether or not a hooking at the end user terminal  32  is detected. When a hooking (on-hook state for a minute interval) is detected, the process step proceeds to a step S 12  in which the PBR  34  is connected to the circuit provided by the exchange  30  so as to be able to detect the push-button signals and convert the same to a corresponding code. As a result of the step S 12 , the system undergoes a transition to a state ready to receive a service code. 
     Next, in the step S 14 , the push-button signals input by the user at the terminal  32  as the service code is received by the PBR  34  and the service code thus supplied is converted by the PBR  34  to a corresponding code or encoded push-button transfer signal. In the step of S 14 , the user may input one of the following service codes: “* 11 ”; “* 12 ”; “* 13 ” and “* 14 ”. 
     *11: No use of the audio-channel  40  for the transfer of signals. Each character is transmitted immediately in real time. 
     *12: No use of the audio-channel  40  for the transfer of signals. The characters are transmitted as a lump in response to detection of the encode character “#”. 
     *13: Use the audio-channel  40  in addition to the signal line  38  for the transfer of signals in addition to the common signal line  38 . Transfer of each character occurs immediately in real time. 
     *14: Use the audio-channel  40  in addition to the signal line  38  for the transfer of signals in addition to the common signal line  38 . The character are transmitted as a lump in response to detection of the encode character “#”. 
     Next, in the step S 16 , a discrimination is made whether or not the service-code setting detected in the step S 14  indicates the use of the audio-channel  40  for the transfer of the push-button signals in addition to the common signal line  38 , and a step S 18  is conducted if the result of the step S 16  is NO and the audio-channel  40  is not to be used for the transfer of the push-button signals. In this case, a forward path of the audio signals, which forms the audio signal channel  40  in the exchange  30  together with a backward audio signal path as indicated in FIG. 6, is disconnected and the state of the exchange  30  changes to the state shown in FIG.  7 . Thereby, the push-button signals are no longer carried to the service system  36  through the audio-channel  40  that connects the exchange  30  to the service system  36 . After the step S 18 , the system undergoes a transition to a push-button signal transfer mode. 
     When the result of the step S 16  is YES and the audio-channel  40  is to be used for transferring signals in addition to the signal line  38 , on the other hand, the system undergoes a transition to the push-button signal transfer mode while maintaining the state of FIG.  6 . 
     Thereafter, a step S 20  is conducted for discriminating whether or not the hooking is detected, and if the result is NO, a further discrimination is made in the step S 22  as to whether or not the push-button signal from the terminal  32  is detected. When a push-button signal is detected, a step S 24  is conducted whether or not the service code indicates the immediate, real time transfer mode. If the result of the step S 24  is YES, the process step proceeds to a step S 26 , wherein the code of the push-button signal detected and converted by the PBR  34  is transferred to the service system  36  as the push-button transfer signal via the common signal line  38 . After the step S 26 , the process step returns to the step S 20 . 
     When the result of the step S 24  is NO and the real time transfer is not necessary, on the other hand, the process step proceeds to a step S 28  wherein a discrimination is made whether or not the current push-button signal indicates the encode character “#”. When the result is NO, the code of the push-button signal detected and converted by the PBR  34  in the step of S 12  is memorized in the step S 30  and the process step returns to the step S 20 . Further, when the result of the step S 28  is YES, the step S 32  is conducted in which the entire memorized codes of the push-button signals are transferred to the service system  36  via the signal line  38  as the push-button transfer signal. In this mode of transfer, a code “F” is added to the end of the transferred codes as a stop digit. 
     Further, when a hooking is detected in the step S 20 , a step S 34  is conducted in which the PBR  34  is disconnected from the circuit under use, and a step S 36  is conducted for restoring the forward path to the state of FIG.  6 . After the step S 36 , the original connection state is restored. 
     FIG. 5 shows the processing conducted by the exchange  30  for processing the push-button signals according to a second embodiment of the present invention. It should be noted that the process of FIG. 5 is carried out for each circuit connection similarly to the process of FIG.  4 . 
     Referring to FIG. 5, a step S 50  is conducted first, in which a discrimination is made whether or not a PBR connection request is received from the service system  36  and the process step proceeds to a step S 52  when the result of the step S 50  is YES. Thereby, the PBR  34  is connected in the step S 52  to the current circuit connection sustained by the exchange  30  for enabling a detection and conversion of the push-button signals to the corresponding codes. 
     Next, in the step S 56 , a discrimination is made whether or not the setting of the PBR connection request indicates use of the audio-channel  40  in addition to the common signal line  38 . If the result is NO, the forward path is disconnected in the step S 58  so that the push-button signals are not transmitted through the audio-channel  40 . After the step S 58 , the system undergoes a transition to a push-button signal transfer mode. When the result of the step S 56  is YES, on the other hand, the system undergoes the transition to the push-button signal transfer mode while maintaining the state of FIG.  6 . 
     After the step S 58 , a step S 60  is conducted in which a discrimination is made whether or not a PBR disconnect request signal is received from the service system  36 , and if the result is NO, a step S 62  is conducted in which a further discrimination is made whether or not the push-button signals from the terminal  32  are detected. If the result of the step S 62  is YES, a step S 64  is conducted in which a discrimination is made whether or not the PBR connection request signal indicates the real time transfer mode. If the result of the step S 64  is YES, the process step proceeds to the step S 66  in which the code of the push-button signals detected by the PBR  34  is transferred to the service system  36  via the common signal line  38  as the push-button transfer signal and the process step returns to the step S 60 . 
     When the result of the step S 64  is NO, on the other hand, the process step proceeds to the step S 68  in which a discrimination is made whether or not the push-button signal represents the encode character “#”. If the result is NO, a step S 70  is conducted in which the code detected and converted by the PBR  34  is memorized and the process step returns to the step S 60 . When the result of the step S 68  is YES, on the other hand, the process step proceeds to the step S 72  and the all the memorized code of the push-button signals are transferred to the service system  36  via the common signal line  38  as the push-button transfer signal and the process returns to the step S 60 . During the transfer of the code in the step S 72 , a code “F” is added to the end of the codes to be transmitted as a stop digit. 
     Further, when the result of the step S 60  is YES and there is a request from the service system  36  to disconnect the PBR  34 , the process step proceeds to the step S 74  and the PBR  34  is disconnected from the current circuit connection. Further, the forward path is restored in the step S 76  as indicated in FIG.  6  and the telecommunication system returns to the original communication state. 
     FIG. 8 shows the format of the push-button transfer signal transmitted from the exchange  30  for the case in which a TUP (telephone user part) protocol is used for the communication protocol between stations. 
     Referring to FIG. 8, the signal format includes a synchronization label at the header part, followed by a heading code “H 0 ” and another heading code “H 1 ” each having four bits, wherein a predetermined code indicative of the push-button transfer signal is set in each of the heading codes H 0  and H 1 . After the heading code H 1 , a four-bit blank part is inserted as a filler, followed by a digit indicative of the relative location of the push-button signal in a succession of the push-button signals. After the foregoing digit, the push-button signals are attached in the form of eight codes each including four bits. Further, the stop digit “F” is inserted at the end of the format as the end code. 
     FIG. 9 shows the signal format used by the service system for requesting the connection or disconnection of the PBR for the case in which the TUP protocol is used for the communication protocol between the stations. 
     Referring to FIG. 9, the format includes a synchronization label at the header part, followed by heading codes H 0  and H 1  each having four bits, wherein a predetermined code indicative of the request for connecting or releasing the PBR is set in the foregoing heading codes H 0  and H 1 . After the heading code H 1 , bits A-H are attached wherein the bits A-H represent the content of the request. For example, the connection request of the PBR  34  may be represented by the digit “ 0 ” of the bit A and the disconnect request of the PBR  34  may be represented by the digit “1”of the same bit A. Similarly, the digit “0” of the bit B may indicate the no-use of the audio channel and the digit “1” of the bit B may indicate the joint use of the audio channel. Further, the digit “0” of the bit C may indicate the real time transfer of the character and the digit “1” of the bit C may indicate the lump transfer of the characters in response to the detection of the end code #. In this case, the bits D-H are not used. 
     FIG. 10 shows the signal format of the push-button transfer signal transmitted by the exchange  30  for the case in which an ISUP (INDS user part) protocol is used for the communication protocol between the stations. 
     Referring to FIG. 10, the header part in the first three octets (octet “0”-octet “2”) holds a predetermined code (message code) indicative of the push-button transfer signal, together with a message length. On the other hand, the octet “3” holds information indicating whether the number of the push-button signal code is odd or even. Further, the octet 5 or later includes two push-button signal codes. 
     FIG. 11 shows the format of the PBR connection/disconnection request signal issued by the service system  36  for the case the ISUP protocol is used for the communication protocol between the stations. 
     Referring to FIG. 11, the first octet or octet “0” holds a predetermined code (message code) indicative of the PBR connection/disconnection request signal, and the next octet “1” holds bits A-H indicative of the content of the request. For example, the digit “0” of the bit A may indicate the connection request of the PBR  34  and the digit “1” of the bit A may indicate the disconnection request of the PBR  34 . Further, the digit “0” of the bit B may indicate the no-use of the audio channel and the digit “1” of the bit B may indicate the joint use of the audio channel. Further, the digit “0” of the bit C may indicate the real time transfer of each character and the digit “1” of the bit C may indicate the lump transfer of the characters in response to the detection of the end code “#.” In this case, the bits D-H are unused. 
     FIG. 12 shows a first example of the operation conducted by the service system  36  for push-button signal reception in the form of a flowchart. The process of FIG. 12 is carried out when it becomes necessary to let the user input the push-button signals. 
     Referring to FIG. 12, the service system  36  sends out an audio guidance to the terminal  32  in the step S 82  for urging the user to hook the phone once and make an appropriate input by pressing down predetermined push buttons or keys, followed by pressing the button “#” when finished. 
     Next, in the step S 84 , the service system  36  receives the push-button transfer signals transmitted over the common signal line  38  from the exchange  30 . After the step S 84 , a step S 86  is conducted in which a discrimination is made whether or not the received push-button signals include the stop digit “F.” When the result is No, the process step returns to the step S 84 , while when the result is YES, the reception of the push-button signals is terminated. 
     FIG. 13 shows a second example of the operation conducted by the service system  36  for push-button signal reception in the form of a flowchart. The process of FIG. 13 is activated when it becomes necessary to let the user of the terminal  32  to input push-button signals. 
     Referring to FIG. 13, the process starts with a step S 90  in which the service system  36  issues a PBR connection request to the exchange  30  that accommodates the line to the user terminal  32 . Next, in the step S 92 , the service system  36  transmits an audio guidance to the user terminal  32  with a message such as “please hook the phone and press predetermined buttons, then please press the button #.” 
     After the step S 92 , the service system  36  receives the push-button transfer signal transmitted from the exchange  30  over the signal line  38 . After discriminating in the step S 96  as to whether or not the received push-button transfer signal includes the stop digit “F,” and the process step returns to the step S 94  when the received push-button transfer signal does not include the stop digit “F.” When there is a stop digit “F,” on the other hand, the process step proceeds to the step S 98  and the service system  36  issues a PBR disconnection request to the exchange  30 . Thereby, the push-button signal processing of the service system  36  is terminated. 
     FIG. 14 shows the process conducted by a relaying exchange provided inside the public network  31  in the form of a flowchart. 
     Referring to FIG. 14, the process starts with a step S 1 OO in which the relaying exchange receives the PBR connection or disconnection request transmitted from the service system  36  over the signal line  38  and the process step proceeds to the next step S 102  wherein the received PBR connection or disconnection request is forwarded to the exchange  30  that accommodates the line connected to the user terminal  32 . Next, the process step proceeds to the step S 104  for receiving the push-button transfer signal transmitted from the exchange  30  over the line  38 , and the push-button transfer signal thus received is forwarded further to the service system  36  in the next step S 106 . 
     In the present invention as explained heretofore, it will be understood that the PBR  34  is connected to the exchange  30  in the state that a circuit connection is established between the user terminal  32  and the service system  36  via the exchange  30 , for detecting the push-button signals supplied from the user terminal  32  and for converting the same to a corresponding code. As the code thus converted is transmitted to the service system  36  over the signal line, it is no longer necessary to provide an additional PBR in the service system  36  and the cost of the service system  36  is reduced substantially. As the code thus obtained by the PBR  34  is transmitted to the service system  36  via the signal line  38 , an excellent transmittance is guaranteed for the push-button signals and the problem of erroneous reception is reduced substantially. 
     In the construction of the present invention in which the PBR  34  is connected to the exchange  30  in response to the hooking at the end user terminal  32  or connection request of the service system  36 , the PBR  34  can perform the detection and encoding of the push-button signal without problem. 
     By disconnecting the forward path of the audio-channel extending from the terminal to the service system at the time of connection of the PBR, unnecessary forward path connection of the audio-channel is eliminated. 
     Further, it is also possible to transmit the push-button signals from the user terminal to the service system also via the audio-channel. Thereby, the telecommunication system of the present invention is applicable also to the case in which the service system has a conventional construction including a PBR. In this case, both the process of the present invention and the process of the prior art shown in FIG. 1 can be used. 
     The state of the telecommunication system returns to the original state in response to the hooking at the end user terminal or in response to the disconnection request from the service system, in which the PBR is disconnected from the exchange  30 . 
     Further, the present invention is not limited to the embodiments described heretofore, but various variations and modifications may be made without departing from the scope of the invention.