Abstract:
A method of registering a service whereby a mobile-communication terminal of a given communication-service provider roaming in a network of a foreign communication-service provider registers a service includes the steps of sending a provider identifier of the foreign communication-service provider from the network to the mobile-communication terminal, storing the provider identifier in the mobile-communication terminal, providing a service-code-correspondence table in the mobile-communication terminal, the table showing correspondences of service codes between a plurality of communication-service providers including the given communication-service provider and the foreign communication-service provider, identifying a service code of the foreign communication-service provider corresponding to a service code of the given communication-service provider by referring to the table and the provider identifier when the service code of the given communication-service provider is entered in the mobile-communication terminal, and sending the service code of the foreign communication-service provider from the mobile-communication terminal to the network.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a method of registering service used when a mobile-communication terminal capable of roaming from an associated communication-service provider to another communication-service provider registers services in a network of the latter communication-service provider.  
           [0003]    2. Description of the Related Art  
           [0004]    In recent years, mobile communication has become widely available as a plurality of communication-service providers offer services over various areas. Since all the communication-service providers do not cover all the areas, some mobile-communication terminals are equipped with a function to roam from one communication-service network to another communication-service network for the purpose of receiving a continuous service between different service areas.  
           [0005]    Each communication-service provider renders various services to subscribers of motile-communication terminals. Some of these services require fees, and others do not. In many cases, communication-service providers require communication-service terminals to register use of or cancellation of a specific service before a requested service takes effect. There are various services such as a call-transfer service, a voice-mail service, etc. A code used for requesting service registration, however, is not unified among the communication-service providers. Since each communication-service provider tends to use a different code for this purpose, a complex procedure is required when a communication-service terminal needs to register services as the terminal moves from a network area of an associated communication-service provider to a new network area of another communication-service provider.  
           [0006]    [0006]FIG. 10 is an illustrative drawing for explaining positional relations between communication-service-provider areas and communication-service terminals.  
           [0007]    In FIG. 10, a wireless base station  80  belongs to a communication-service provider A, and a wireless base station  81  belongs to a communication-service provider B. A communication-service terminal  82  is a subscriber of the communication-service provider B, and is currently positioned in an area covered by the communication-service provider A. A communication-service terminal  83  is a subscriber of the communication-service provider B, and is located in an area of the communication-service provider B. Further, a communication-service terminal  84  belongs to the communication-service provider A, and is situated in the area of the communication-service provider A. A switch  85  is provided for the wireless base station  80 , and is a facility of the communication-service provider A. A switch  86  is provided for the wireless base station  81 , and is a facility of the communication-service provider B.  
           [0008]    In the mobile-communication system as shown in FIG. 10, the communication-service terminals  83  and  84  are allowed to roam between the two communication-service-provider networks. When the communication-service terminal  84  currently positioned in the area of the communication-service provider A (area of the wireless base station  80 ) needs to register use or cancellation of services such as a call-transfer service, a voice-mail service, and a call-waiting service, the communication-service terminal  84  dials a code (number) that is specified by the communication-service provider A. In detail, for example, a code “1421” is dialed when requesting registration for adding a call-transfer service, and a code “1420” is dialed when requesting registration for canceling a call-transfer service. When the wireless base station  80  receives a code, the switch  85  analyzes the code so as to identify a request. Then, subscriber data of the communication-service terminal  84  is registered to add or cancel a call-transfer service.  
           [0009]    By the same token, when the communication-service terminal  83  currently positioned in the area of the communication-service provider B (area of the wireless base station  81 ) needs to register use or cancellation of a call-transfer service, the communication-service terminal  83  dials a code (number) that is specified by the communication-service provider B. For example, a code “112” is used for adding a call-transfer service, and a code “114” is used for canceling a call-transfer service. When the wireless base station  81  receives these codes, the switch  86  analyzes the codes to identify the requests, and, then, subscriber data is registered accordingly.  
           [0010]    In the following, a description will be provided with regard to a case in which the communication-service terminal  82  requests registration for use of services by using service codes that are defined by a communication-service provider B.  
           [0011]    [0011]FIG. 11 is a block diagram of the switch  85 . In FIG. 11, the same elements as those of FIG. 10 are referred to by the same numerals, and a description thereof will be omitted.  
           [0012]    The switch  85  includes a service-code-input unit  850 , a service-code-analysis unit  851 , subscriber data  852 , a service providing unit  853 , and a service-code-correspondence table  854 . The service-code-input unit  850  receives a service code sent from the wireless base station  80 . The service-code-analysis unit  851  analyzes the received service code. The service providing unit  853  renders a service that is requested by the communication-service terminal  82 . The service-code-correspondence table  854  stores all the codes used by the communication-service providers, and makes it possible to match one code with another where the communication-service providers use different service codes.  
           [0013]    The communication-service terminal  82 , which is roaming in the area of the communication-service provider A, needs to register use of a call-transfer service. In this case, the communication-service terminal  82  transmits a signal carrying the code “112” that is defined by the communication-service provider B, and this signal is input to the service-code-input unit  850  of the switch  85  via the wireless base station  80 . Then, the service-code-analysis unit  851  determines which communication-service provider is used by the communication-service terminal  82  based on a terminal number that is received from the communication-service terminal  82  along with the service code.  
           [0014]    As the terminal number reveals that the communication-service terminal  82  belongs to the communication-service provider B, the received service code is searched for among codes of the communication-service provider B in the service-code-correspondence table  854 . As a result, the received service code is identified as a code for adding a call-transfer service.  
           [0015]    The received service code of the communication-service provider B is then converted into a corresponding service code of the communication-service provider A, and registration is effected in the subscriber data  852 . Further, the subscriber data and a description of the requested service (or service code of the communication-service provider B) are sent to the switch  86  (FIG. 10) that belongs to the communication-service provider B. The service providing unit  853  renders a service according to what is registered in the subscriber data  852 .  
           [0016]    In order to cope with a service-registration request received from a communication-service terminal that is residing in a foreign communication-service-provider network, a switch needs to be provided with all the service codes of all the communication-service providers which permit roaming. Further, the switch needs to convert the received service code after identifying the associated communication-service provider of the communication-service terminal. This requires a complex control procedure, resulting in a low efficiency of call processing control of the switch.  
           [0017]    Accordingly, there is a need for a method of registering services which is based on a simple control procedure so as to achieve prompt processing when a communication-service terminal requests service registration in a foreign communication-service-provider network.  
         SUMMARY OF THE INVENTION  
         [0018]    Accordingly, it is a general object of the present invention to provide a method of registering services which can satisfy the need described above.  
           [0019]    It is another and more specific object of the present invention to provide a method of registering services which is based on a simple control procedure so as to achieve prompt processing when a communication-service terminal requests service registration in a foreign communication-service-provider network.  
           [0020]    In order to achieve the above object, a method of registering a service whereby a mobile-communication terminal of a given communication-service provider roaming in a network of a foreign communication-service provider registers a service includes the steps of sending a provider identifier of the foreign communication-service provider from the network to the mobile-communication terminal, storing the provider identifier in the mobile-communication terminal, providing a service-code-correspondence table in the mobile-communication terminal, the table showing correspondences of service codes between a plurality of communication-service providers including the given communication-service provider and the foreign communication-service provider, identifying a service code of the foreign communication-service provider corresponding to a service code of the given communication-service provider by referring to the table and the provider identifier when the service code of the given communication-service provider is entered in the mobile-communication terminal, and sending the service code of the foreign communication-service provider from the mobile-communication terminal to the network.  
           [0021]    In the method as described above, the provider identifier is given from the network to the mobile-communication terminal, so that the mobile-communication terminal can identify which communication-service provider covers an area where the mobile-communication terminal is currently positioned. Also, the mobile-communication terminal is provided with the service-code-correspondence table. This allows the mobile-communication terminal to identify a service code of the foreign communication-service provider corresponding to a service code of the given communication-service provider when the service code of the given communication-service provider is entered in the mobile-communication terminal. The mobile-communication terminal thus can send the service code of the foreign communication-service provider that covers an area where the mobile-communication terminal is currently located.  
           [0022]    According to another aspect of the present invention, a method of registering a service whereby a mobile-communication terminal of a given communication-service provider roaming in a network of a foreign communication-service provider registers a service includes the steps of sending a correspondence table from the network to the mobile-communication terminal, the table showing correspondences between service codes of the foreign communication-service provider and service codes of a plurality of communication-service providers including the given communication-service provider, storing the table in the mobile-communication terminal, identifying a service code of the foreign communication-service provider corresponding to a service code of the given communication-service provider by referring to the table when the service code of the given communication-service provider is entered in the mobile-communication terminal, and sending the service code of the foreign communication-service provider from the mobile-communication terminal to the network.  
           [0023]    In the method as described above, the table is sent from the network to the mobile-communication terminal, and the table is configured such that the mobile-communication terminal can identify service codes of the foreign communication-service provider that covers an area where the mobile-communication terminal is currently positioned. This allows the mobile-communication terminal to identify a service code of the foreign communication-service provider corresponding to a service code of the given communication-service provider when the service code of the given communication-service provider is entered in the mobile-communication terminal. The mobile-communication terminal thus can send the service code of the foreign communication-service provider that covers an area where the mobile-communication terminal is currently located.  
           [0024]    According to another aspect of the present invention, a method of registering a service whereby a mobile-communication terminal of a given communication-service provider roaming in a network of a foreign communication-service provider registers a service includes the steps of sending a service code of the given communication-service provider and a provider identifier directly indicating the given communication-service provider from the mobile-communication terminal to a switch of the network when the service code of the given communication-service provider is entered in the mobile-communication terminal, and identifying, in the switch, a service code of the foreign communication-service provider corresponding to the service code of the given communication-service provider by referring to the provider identifier and a table which shows correspondences of service codes between a plurality of communication-service providers including the given communication-service provider and the foreign communication-service provider.  
           [0025]    In the method described above, the provider identifier identifies the provider with which the mobile-communication terminal is associated as a subscriber, and the mobile-communication terminal sends the provider identifier to the switch of the network along with the service code of the given communication-service provider. This allows the switch to easily identify the service code of the foreign communication-service provider corresponding to the service code of the given communication-service provider since the provider identifier directly indicates the given communication-service provider among many other communication-service providers.  
           [0026]    Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    [0027]FIG. 1 is a block diagram showing a configuration of a system according to a first principle of the present invention;  
         [0028]    [0028]FIG. 2 is a block diagram showing a configuration of a system according to a second principle of the present invention;  
         [0029]    [0029]FIG. 3 is a block diagram of a configuration of a system according to a first embodiment of the present invention;  
         [0030]    [0030]FIG. 4 is a block diagram of a mobile-communication terminal according to the first embodiment;  
         [0031]    [0031]FIG. 5 is a sequence chart of operations performed according to the first embodiment;  
         [0032]    [0032]FIG. 6 is a block diagram of a configuration of a system according to a second embodiment of the present invention;  
         [0033]    [0033]FIG. 7 is a block diagram of a mobile-communication terminal according to the second embodiment;  
         [0034]    [0034]FIG. 8 is an illustrative drawing showing an example of the service-code-to-switch-side-service-code correspondence table;  
         [0035]    [0035]FIG. 9 is a sequence chart showing operations performed according to the second embodiment of the present invention;  
         [0036]    [0036]FIG. 10 is an illustrative drawing for explaining positional relations between communication-service-provider areas and communication-service terminals;  
         [0037]    [0037]FIG. 11 is a block diagram of a switch of the related art.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]    In the following, principles and embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0039]    [0039]FIG. 1 is a block diagram showing a configuration of a system according to a first principle of the present invention.  
         [0040]    In FIG. 1, a mobile-communication terminal  1  includes an input unit  1   a,  a provider-information-detection unit  1   b,  a provider-identifier-storage unit  1   c,  a service-code-correspondence table  1   d,  a service-code-analysis unit  1   e,  and a signal-output unit  1   f.  The provider-information-detection unit  1   b  detects provider information including a provider identifier when relevant information is received from a base station. The provider-identifier-storage unit  1   c  stores a provider identifier. The service-code-correspondence table  1   d  stores service codes of communication-service providers by matching the service codes of the same service contents between different communication-service providers. The service-code-analysis unit le analyzes a received service code, and converts the received service code into a service code that is used by a communication-service provider of a currently positioned area where the mobile-communication terminal  1  is currently positioned. The signal-output unit if outputs a signal to a base station by using the service code of the communication-service provider of the currently positioned area. Further, a wireless base station  2 , which is provided in the currently positioned area, includes a provider-identifier-notification unit  2   a.  The provider-identifier-notification unit  2   a  informs a mobile-communication terminal of a provider identifier, which indicates a communication-service provider that owns the wireless base station  2 , when the mobile-communication terminal is positioned in its area of control. Further, the wireless base station  2  is connected to the switch device  3 .  
         [0041]    In FIG. 1, the mobile-communication terminal  1  belongs to a communication-service provider that is different from the communication-service provider that owns the wireless base station  2 . The provider-identifier-notification unit  2   a  of the wireless base station  2  transmits a provider identifier of the communication-service provider that owns the wireless base station  2  at constant intervals or within constant intervals. Each mobile-communication terminal residing in the area covered by the wireless base station  2  receives the provider identifier as a signal, and the provider-information-detection unit  1   b  of the mobile-communication terminal  1  obtains the provider information from the received signal. The provider-information-detection unit  1   b  stores the obtained provider identifier in the provider-identifier-storage unit  1   c.  A user of the mobile-communication terminal  1  requests registration of a particular service by entering a relevant service code, which is defined by the communication-service provider of the mobile-communication terminal  1 . When the service code is entered, the input unit  1   a  detects the service code, and the service-code-analysis unit le analyzes the service code. Namely, the service-code-correspondence table id is referred to, and the detected service code is searched for among the service codes of the communication-service provider of the mobile-communication terminal  1 . Based on the stored correspondences between different communication-service providers, a service code of the communication-service provider identified by the provider identifier stored in the provider-identifier-storage unit  1   c  is obtained. The obtained service code is transmitted from the signal-output unit if to the wireless base station  2 . The switch device  3  analyzes this service code to attend to necessary processing.  
         [0042]    [0042]FIG. 2 is a block diagram showing a configuration of a system according to a second principle of the present invention. In FIG. 2, the same elements as those of FIG. 1 are referred to by the same numerals.  
         [0043]    The mobile-communication terminal  1  includes the input unit  1   a,  the provider-information-detection unit  1   b,  the signal-output unit if, a service-code-to-switch-side-service-code correspondence table  1   g,  and a service-code-analysis unit  1   h.  The service-code-to-switch-side-service-code correspondence table  1   g  is received from the switch device  3  via the wireless base station  2 . The switch device  3  includes a service-code-correspondence-table notifying unit  3   a  for sending the service-code-to-switch-side-service-code correspondence table  1   g.  The service-code-to-switch-side-service-code correspondence table  1   g  stores service codes and switch-side service codes by keeping correspondences therebetween. Here, the stored service codes are those used by foreign communication-service providers for the purpose of requesting services, and the stored switch-side service codes are those defined by the communication-service provider that owns the wireless base station  2  and the switch device  3 .  
         [0044]    The mobile-communication terminal  1  belongs to a communication-service provider that is different from the communication-service provider that owns the wireless base station  2 . When the service-code-correspondence-table notifying unit  3   a  of the switch device  3  transmits the service-code-to-switch-side-service-code correspondence table to the mobile-communication terminal  1 , the provider-information-detection unit  1   b  of the mobile-communication terminal  1  obtains the table, and stores it as the service-code-to-switch-side-service-code correspondence table  1   g.  The service-code-to-switch-side-service-code correspondence table may be set in the wireless base station  2  by the switch device  3 , and the wireless base station  2  may periodically transmit the table to the communication-service terminals residing in its area of control.  
         [0045]    A user of the mobile-communication terminal  1  requests registration of a particular service by entering a relevant service code, which is defined by the communication-service provider of the mobile-communication terminal  1 . When the service code is entered, the input unit  1   a  detects the service code, and the service-code-analysis unit  1   h  analyzes the service code. Namely, the service-code-analysis unit  1   h  refers to the service-code-to-switch-side-service-code correspondence table  1   g,  and searches for the detected service code to identify a corresponding switch-side service code. The identified switch-side service code is transmitted from the signal-output unit if to the switch device  3  via the wireless base station  2 . The switch device  3  analyzes the switch-side service code to attend to requested processing.  
         [0046]    As an alternative approach, the related-art configuration of FIG. 11 may be modified such that the communication-service terminal  82  sends a provider identifier and a service request to the switch  85  at the time of service registration. (In the related art, the provider identity was found by analyzing a terminal number.) Upon receiving the provider identifier and the service request, the switch  85  uses the service-code-analysis unit  851  to refer to the service-code-correspondence table  854 , and finds a corresponding service code to attend to necessary processing.  
         [0047]    In the following, embodiments of the present invention will be described.  
         [0048]    [0048]FIG. 3 is a block diagram of a configuration of a system according to a first embodiment of the present invention. FIG. 4 is a block diagram of a mobile-communication terminal according to the first embodiment. The first embodiment corresponds to the first principle described above.  
         [0049]    The system of FIG. 3 includes the mobile-communication terminal  1 , the wireless base station  2 , and the switch device  3 . The switch device  3  includes a service-code-input unit  30 , a service-code-analysis unit  31 , a subscriber-data-storage unit  32 , and a service providing unit  33 . The service-code-input unit  30  receives a service code from the wireless base station  2 . The subscriber-data-storage unit  32  stores locations, registration data of registered services, etc., with respect to each subscriber.  
         [0050]    The mobile-communication terminal  1  of FIG. 4 includes a service-code-input unit  10 , a service-code-analysis unit  11 , a provider-identifier-storage unit  12 , a service-code-correspondence table  13 , a provider-information-detection unit  14 , a signal-output unit  15 , and a wireless-communication unit  16 . The service-code-analysis unit  11  analyzes an entered service code based on the service-code-correspondence table  13 . The provider-identifier-storage unit  12  stores a provider identifier received from the wireless base station  2 . The service-code-correspondence table  13  stores service codes of all the communication-service providers with respect to each type of service request. The provider-information-detection unit  14  detects a provider identifier sent from the wireless base station  2 . The signal-output unit  15  transmits a service code to the wireless base station  2 . The wireless-communication unit  16  is used for wireless communication.  
         [0051]    In the first embodiment, the service-code-correspondence table  13  of the mobile-communication terminal  1  stores service codes of all communication-service providers (service provider A, service provider B, and so on) with respect to each type of a requested service such as use of a call-transfer service, cancellation of a call-transfer service, use of a voice-mail service, cancellation of a voice-mail service, etc. The service-code-correspondence table  13  is stored in the mobile-communication terminal  1  in advance, and can be updated or rewritten externally.  
         [0052]    [0052]FIG. 5 is a sequence chart of operations performed according to the first embodiment. FIG. 5 shows relations of operations between the service-code-analysis unit  11 , the provider-identifier-storage unit  12 , the wireless base station  2 , and the switch device  3 . Operations of other elements are omitted as being secondary to the above operations shown in the figure.  
         [0053]    In what follows, the operation of the first embodiment will be described with reference to FIG. 3 through FIG. 5.  
         [0054]    The wireless base station  2  stores in a memory thereof a provider identifier of a provider that owns the wireless base station  2 . The provider identifier may be set by the switch device  3 , or may be set internally in the wireless base station  2 . The wireless base station  2  transmits provider information including the provider identifier to mobile-communication terminals residing in its area of control at constant intervals (step S 1  of FIG. 5). The mobile-communication terminal  1  currently residing in this area receives the provider information via the wireless-communication unit  16 . The provider-information-detection unit  14  detects the provider identifier, and stores it in the provider-identifier-storage unit  12  (step S 2  of FIG. 5).  
         [0055]    A user of the mobile-communication terminal  1  dials a service code via the service-code-input unit  10  in order to register a service corresponding to the dialed service code. This service code is one of the codes used by a communication-service provider with which the user is associated as a subscriber. In response, the service-code-analysis unit  11  of the mobile-communication terminal  1  is activated to detect the entered service code (step S 3  of FIG. 5). The service-code-analysis unit  11  then obtains the provider identifier from the provider-identifier-storage unit  12  (step S 4  of FIG. 5).  
         [0056]    The service-code-analysis unit  11  obtains a corresponding service code equivalent to the detected service code by using the service-code-correspondence table  13  such that the corresponding service code is one that is used by the communication-service provider identified by the provider identifier (step S 5  of FIG. 5). The corresponding service code is output from the signal-output unit  15  as a signal requesting a service registration, and is transmitted to the wireless base station  2  via the wireless-communication unit  16 . This signal is forwarded from the wireless base station  2  to the switch device  3 , where the service code is analyzed, and a requested service is provided (step S 6  of FIG. 5).  
         [0057]    In the switch device  3 , when the service-code-input unit  30  receives the service code from the mobile-communication terminal  1 , the service-code-analysis unit  31  can readily identify the service code since this code is the one used by no other than the communication-service provider to which the switch device  3  belongs. An identified result is stored in the subscriber-data-storage unit  32  as part of the data of the pertinent subscriber. If the mobile-communication terminal  1  is associated with a foreign communication-service provider, data of the requested service is transmitted to the foreign communication-service provider after the data is stored in the subscriber-data-storage unit  32 . Alternatively, the data may not be stored in the subscriber-data-storage unit  32 , and may be just sent to the foreign communication-service provider. The service providing unit  33  is activated by the service-code-analysis unit  31 , and provides the requested service to a location of the subscriber as the location is registered in the subscriber-data-storage unit  32 . When the data is registered in a switch of the foreign communication-service provider, this switch attends to necessary processing.  
         [0058]    An example of a service-code conversion according to the first embodiment will be described below. The mobile-communication terminal  1  belongs to the communication-service provider B, and requests use of a voice-mail service via dialing of a number “116”. The dialed number is detected by the service-code-analysis unit  11  of the mobile-communication terminal  1 , and, then, the service-code-correspondence table  13  is referred to so as to identify use of a voice-mail service as a requested service. Since the provider-identifier-storage unit  12  has the provider identifier of the communication-service provider A stored therein, a service code of the communication-service provider A for the voice-mail service is looked for in the service-code-correspondence table  13 . A service code “1411” is thus obtained. The service code “1411” is then sent from the signal-output unit  15  to the wireless base station  2  and the switch device  3 .  
         [0059]    [0059]FIG. 6 is a block diagram of a configuration of a system according to a second embodiment of the present invention. FIG. 7 is a block diagram of a mobile-communication terminal according to the second embodiment. The second embodiment corresponds to the second principle described above.  
         [0060]    In FIG. 6 and FIG. 7, the same elements as those of FIG. 3 and FIG. 4 are referred to by the same numerals, and a description thereof will be omitted. In FIG. 7, the mobile-communication terminal  1  includes a correspondence-table-storage unit  17  for storing a service-code-to-switch-side-service-code correspondence table. The switch device  3  of FIG. 6 includes a service-code-to-switch-side-service-code correspondence table  34 .  
         [0061]    The service-code-to-switch-side-service-code correspondence table  34  stores service codes that are used for requesting service, and are defined by each one of foreign communication-service providers. The service-code-to-switch-side-service-code correspondence table  34  further stores switch-side service codes that are defined by the communication-service provider to which the wireless base station  2  and the switch device  3  belong. The service-code-to-switch-side-service-code correspondence table  34  provides correspondences between the service codes and the switch-side service codes.  
         [0062]    [0062]FIG. 8 is an illustrative drawing showing an example of the service-code-to-switch-side-service-code correspondence table  34 .  
         [0063]    As shown in FIG. 34, the service-code-to-switch-side-service-code correspondence table  34  stores service codes of the foreign communication-service providers A and B with respect to each type of service such as use of a call-transfer service, cancellation of a call-transfer service, use of a voice-mail service, cancellation of a voice-mail service, etc. The last column of the table has entries of the switch-side service codes that are employed by the communication-service provider of the wireless base station  2  and the switch device  3 .  
         [0064]    [0064]FIG. 9 is a sequence chart showing operations performed according to the second embodiment of the present invention. FIG. 9 shows mutual operational relations between the service-code-analysis unit  11 , the correspondence-table-storage unit  17 , the wireless base station  2 , and the switch device  3 . Operations of other elements are omitted as being secondary to the operations shown in the figure.  
         [0065]    In what follows, the operation of the second embodiment will be described with reference to FIG. 6 through FIG. 9.  
         [0066]    The wireless base station  2  receives provider information including the service-code-to-switch-side-service-code correspondence table  34  from the switch device  3 , and transmits the provider information to the mobile-communication terminal  1  (step S 1  of FIG. 9). The mobile-communication terminal  1  currently residing in the area of the wireless base station  2  receives the provider information via the wireless-communication unit  16 . The provider-information-detection unit  14  detects the provider information, and stores the service-code-to-switch-side-service-code correspondence table in the correspondence-table-storage unit  17  (step S 2  of FIG. 9).  
         [0067]    A user of the mobile-communication terminal  1  dials a service code via the service-code-input unit  10  in order to register a service corresponding to the dialed service code. This service code is one of the codes used by a communication-service provider with which the user is associated as a subscriber. In response, the service-code-analysis unit  11  of the mobile-communication terminal  1  is activated to detect the entered service code (step S 3  of FIG. 9). The service-code-analysis unit  11  then obtains the contents of the correspondence-table-storage unit  17  (step S 4  of FIG. 9).  
         [0068]    The service-code-analysis unit  11  obtains a switch-side service code corresponding to the detected service code by using the service-code-to-switch-side-service-code correspondence table (step S 5  of FIG. 9). The switch-side service code is output from the signal-output unit  15  as a signal requesting a service registration, and is transmitted to the wireless base station  2  via the wireless-communication unit  16 . This signal is forwarded from the wireless base station  2  to the switch device  3 , where the service code is analyzed, and a requested service is provided (step S 6  of FIG. 9).  
         [0069]    An example of a service-code conversion will be given below with reference to the service-code-to-switch-side-service-code correspondence table shown in FIG. 8.  
         [0070]    When the mobile-communication terminal  1  belonging to the communication-service provider B requests use of a voice-mail service through dialing of a number “116”, the service-code-analysis unit  11  of the mobile-communication terminal  1  detects the dialed number. Then, the service-code-to-switch-side-service-code correspondence table of FIG. 8 is referred to, and a switch-side service code “#31” is extracted as a code corresponding to the number “116”. The extracted service code “#31” is then sent from the signal-output unit  15  to the wireless base station  2  and the switch device  3 .  
         [0071]    As described above, the present invention eliminates a need for a switch to have a whole series of service codes of all the communication-service providers that permit roaming, thereby avoiding a need for a huge database and a complex processing procedure. This reduces the load of code conversion on the switch, and makes it possible to perform high-speed call processing and to enhance reliability of the switch.  
         [0072]    Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.  
         [0073]    The present application is based on Japanese priority application No. 10-290188 filed on Oct. 13, 1998, with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.