WO2008136606A1

WO2008136606A1 - System and method for roaming bidirectionally

Info

Publication number: WO2008136606A1
Application number: PCT/KR2008/002495
Authority: WO
Inventors: Sug Woon Kim
Original assignee: Sug Woon Kim
Priority date: 2007-05-03
Filing date: 2008-05-02
Publication date: 2008-11-13
Also published as: KR100850109B1

Abstract

Provided is a bidirectional roaming system and method. The bidirectional roaming system executes a bidirectional roaming service between a first country and at least one second country which is different from the first country, and includes a main server and at least one local server. The main server is installed in the first country, determines a main temporary number corresponding to a phone number of a subscriber of the first country, and connects the main temporary number to which a call incoming at the phone number is forwarded to a local roaming number connected to the main temporary number upon arrival of a call forwarding period in order to transmit and receive data through a communication line corresponding to the local roaming number. The local server is installed in the second country, determines a local temporary number corresponding to the local roaming number, and connects the local temporary number to which a call incoming at the local roaming number is forwarded to the phone number connected to the local temporary number upon arrival of a reverse call forwarding period in order to transmit and receive data through the communication line. The bidirectional roaming system allows users not only to use a roaming service with low cost, but also to receive a call incoming at a roaming number used in a foreign country even after returning to a home country from the foreign country.

Description

[DESCRIPTION] [Invention Title]

System and method for roaming bidirectionally [Technical Field] The present invention generally relates to a bidirectional roaming system and method, and more particularly, to a bidirectional roaming system and method by which it is possible not only to roam a call incoming at a phone number of a first country (or a first-country phone number) to a roaming number of a second country (or a second- country roaming number) but also to roam a call incoming at the second-country roaming number to the first- country phone number.

[Background Art]

With the recent rapid increase in demand for mobile communications, there is also increasing demand for global roaming enabling a user to receive and make calls with the same phone number from anywhere in the world. Domestic mobile communication networks adopt a synchronous Code Division Multiple Access (CDMA) scheme.

However, most CDMA users feel inconvenience for lack of a service allowing them to continue receiving mobile communication services with their terminals in foreign countries. While Global System for Mobile communication (GSM), which currently occupies 80% of the entire mobile communication market, has been designed and established taking into account smooth communications between countries of Europe, CDMA does not fully reflect needs for mobile communication services between countries. In CDMA mobile communication, only a single Mobile Identification

Number (MIN) can be used for a single Electronic Serial Number (ESN). As a result, in principle, a user cannot subscribe to a plurality of mobile communication services by using a single mobile communication terminal or a plurality of subscribers cannot use together a single mobile communication terminal.

On the other hand, in GSM mobile communication, a Subscriber Identify Module (SIM) card having embedded therein a semiconductor integrated circuit is used. Authentication related information for each user is recorded in an SIM card, so that the user can consume a GSM mobile communication service of a corresponding country with a single terminal in various countries by inserting different SIM cards into the terminal for common carriers of different countries.

As such, since a user cannot consume a mobile communication service with a single mobile communication terminal in a plurality of countries due to a communication standard based on one-to-one correspondence between an ESN and a MIN, the user has conventionally consumed a mobile communication service in different countries by using the following method. In other words, an international roaming service may be used. The international roaming service is a service allowing subscribers to continue receiving a mobile communication service with their existing phone numbers and mobile communication terminals in foreign countries. The international roaming service can be classified into an automatic roaming service and a semi-automatic roaming service.

The automatic roaming service enables users to receive a mobile communication service in various countries by using their own dedicated mobile communication terminals capable of adapting to a frequency band and a communication scheme of each intended country. The semi-automatic roaming service enables users to receive a mobile communication service in foreign countries by using a rental terminal capable of receiving a call incoming at their phone numbers as previously agreed in airports, etc.

However, the international roaming service has some problems. First, charges for the service are expensive. For example, if a caller originating from a first country (or a first-country caller) makes a call to a user originating from the first country (or a first-country user) while the first-country user stays in a second country, such a call has to pass through both a common carrier of the first country and a common carrier of the second country and an expensive charge has to be paid according to an agreement between the common carriers.

When the first-country user uses a mobile phone in the second country by consuming a roaming service, if a caller originating from the second country (or a second-country caller) makes a call to the first- country user staying in the second country, the call becomes an international call from the second country to the first country such that it passes through a mobile communication service network to which the first- country user subscribes in the first country, and then the call becomes an international call from the first country to the second country such that it is connected to a mobile communication network of the second country aligned with a mobile communication service of the first country, and then finally the call is connected to the first-country user staying in the second country through the mobile communication network of the second country. As a result, although the call is made within the second country, a charge two times higher than an international call charge has to be paid.

If the first-country user returns to the first country from the second country, the roaming service is terminated, resulting in a failure to receive a call incoming at a roaming phone number having been used in the second country.

Therefore, there is a need for a new roaming method which allows users to use a roaming service with low cost and to receive a call incoming at a roaming number having been used in a foreign country after returning to a home country. [Disclosure] [Technical Problem]

The present invention a bidirectional roaming system by which it is possible not only to roam a call incoming at a first-country phone number to a second-country roaming number but also to roam a call incoming at the second-country roaming number to the first-country phone number.

The present invention also provides a bidirectional roaming method by which it is possible not only to roam a call incoming at a first-country phone number to a second-country roaming number but also to roam a call incoming at the second-country roaming number to the first-country phone number.

[Technical Solution]

According to an aspect of the present invention, there is provided a bidirectional roaming system for executing a bidirectional roaming service between a first country and at least one second country which is different from the first country. The bidirectional roaming system includes a main server and at least one local server. The main server is installed in the first country, determines a main temporary number corresponding to a phone number of a subscriber of the first country, and connects the main temporary number to which a call incoming at the phone number is forwarded to a local roaming number connected to the main temporary number upon arrival of a call forwarding period in order to transmit and receive data through a communication line corresponding to the local roaming number. The local server is installed in the second country, determines a local temporary number corresponding to the local roaming number, and connects the local temporary number to which a call incoming at the local roaming number is forwarded to the phone number connected to the local temporary number upon arrival of a reverse call forwarding period in order to transmit and receive data through the communication line. The main server may include a transmitting/receiving unit, a main connection processing unit, a main communication control unit, and an information storing unit. The transmitting/receiving unit receives subscriber information including the phone number, the call forwarding period, and the reverse call forwarding period. The main connection processing unit determines the main temporary number corresponding to the subscriber information, requests call forwarding from the phone number to the main temporary number upon arrival of the call forwarding period, and connects the main temporary number to the local roaming number. The main communication control unit transmits and receives data to and from the local server through the communication line. The information storing unit stores the subscriber information, local information including the local roaming number and the local temporary number, and line information of the communication line. The transmitting/receiving unit may receive the subscriber information through the Internet or a wired/wireless phone and transmit the local roaming number corresponding to the phone number to the subscriber.

The main communication control unit may include a main gateway and a main gatekeeper. The main gateway transmits and receives data to and from the local server through the communication line. The main gatekeeper performs number management for the main gateway.

The main communication control unit may further include a reception gateway and a reception gatekeeper. The reception gateway receives data being input from outside. The reception gatekeeper performs number management for the reception gateway.

The local server may include a local connection processing unit and a local communication control unit. The local connection processing unit determines the local temporary number corresponding to the local roaming number, requests call forwarding from the local roaming number to the local temporary number upon arrival of the reverse call forwarding period, and connects the local temporary number to the phone number connected to the local temporary number. The local communication control unit transmits and receives data to and from the main server through the communication line.

The local communication control unit may include a local gateway and a local gatekeeper. The local gateway transmits and receives data to and from the main server through the communication line. The local gatekeeper performs number management for the local gateway. The main temporary number and/or the local temporary number may use Direct Inward Dialing (DID).

The communication line may be one of a Voice over Internet Protocol (VoIP) line, an international phone line, and a Direct Outward Dialing (DOD) line. According to another aspect of the present invention, there is provided a bidirectional roaming method for executing a bidirectional roaming service between a first country and at least one second country which is different from the first country. The bidirectional roaming method includes receiving subscriber information of a subscriber of the first country, the subscriber information including a phone number, a call forwarding period, and a reverse call forwarding period, determining a main temporary number corresponding to the subscriber information, connecting the main temporary number to which a call incoming at the phone number is forwarded to a local roaming number upon arrival of the call forwarding period in order to transmit and receive data through a communication line corresponding to the local roaming number, and determining a local temporary number corresponding to the local roaming number and connecting the local temporary number to which a call incoming at the local roaming number is forwarded to the phone number connected to the local temporary number upon arrival of the reverse call forwarding period in order to transmit and receive data through the communication line.

The receiving of the subscriber information may include receiving the subscriber information by using the Internet or a wired/wireless phone and transmitting the local roaming number corresponding to the phone number to the subscriber.

The transmitting and receiving of the data upon arrival of the call forwarding period may include requesting call forwarding from the phone number to the main temporary number and connecting the main temporary number to the local roaming number and transmitting and receiving data to and from the local server through the communication line. The transmitting and receiving of the data upon arrival of the reverse call forwarding period may include requesting call forwarding from the local roaming number to the local temporary number and connecting the local temporary number to the phone number connected to the local temporary number and transmitting and receiving data to and from the main server through the communication line.

[Advantageous Effects]

As described above, the bidirectional roaming system and method according to an embodiment of the present invention allows users not only to use a roaming service with low cost, but also to receive a call incoming at a roaming number used in a foreign country even after returning to a home country from the foreign country. [Description of Drawings]

FIG. 1 illustrates the structure of a bidirectional roaming system according to an embodiment of the present invention; and FIG. 2 is a flowchart illustrating a bidirectional roaming method according to an embodiment of the present invention.

[Best Mode]

In order to sufficiently understand the present invention, advantages of the present invention, and purposes achieved by the following embodiment of the present invention, the following description must be referred to the accompanying drawings and the description contained in the drawings.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that like reference numerals refer to like elements illustrated in one or more of the drawings.

In general, a subscriber is assigned a phone number by subscribing to a common carrier in a first country (or a home country) and is continuously provided with a communication service through the assigned phone number. A bidirectional roaming system according to an embodiment of the present invention provides a service which not only allows the subscriber to receive a call incoming at a first-country phone number through a second-country roaming number while staying in a second country (or a visited country), but also allows the subscriber to receive a call incoming at the second-country roaming number through the first- country phone number even after returning to the first country.

Hereinafter, the structure of a bidirectional roaming system 100 for providing those services will be described with reference to FIGS. 1 and 2. FIG. 1 illustrates the structure of the bidirectional roaming system 100 according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a bidirectional roaming method according to an embodiment of the present invention. The bidirectional roaming system 100 executes a bidirectional roaming service in a first country and at least one second country which is different from the first country, and includes a main server 110 and at least one local servers 130_l through 130_N, and 130. To facilitate understanding of the operation of the bidirectional roaming system 100, subscribers 190 (for the subscriber in the first country) and 190^' (for the subscriber in the second country), callers 170 and 180, a first-country communication network 140, a second-country communication network 160, and a communication line 120 are also illustrated in FIG. 1 in addition to the main server 110 and the local servers 130_l through 130_N, and 130.

The main server 110 is preferably installed in the first country and the local servers 130_l through 130_N, and 130 are preferably installed in the second country. Although the structure of only the local server 130 among the local servers 130_l through 130_N, and 130 is illustrated in FIG. 1 for convenience of explanation, the structures of the local servers 130_l through 130_N may also be implemented in a similar manner to the local server 130. Referring to FIG. 1, the main server 110 includes a transmitting/receiving unit 111, a connection processing unit 113, a main communication control unit 115, and an information storing unit 119. The main server 110 may further include a charge processing unit 117. The subscriber 190 who desires a roaming service may access the bidirectional roaming system 100 according to an embodiment of the present invention through the first-country communication network 140 in order to apply for the service.

The first-country communication network 140 may be not only a wired/wireless phone network but also an arbitrary communication network available in the first country such as an Internet network. The subscriber 190 may access the main server 110 through the Internet network to input subscriber information according to a guide screen, or may access the main server 110 through a wired/wireless phone to input subscriber information according to ARS voice.

In operation S201, the transmitting/receiving unit 111 receives the subscriber information which is input by the subscriber 190 during the application for the service. The subscriber information includes not only information necessary for roaming such as a phone number, a main temporary number, a call forwarding period, and a reverse call forwarding period of the subscriber 190 in the first country, and a country name and a city name of the second country to be visited, but also general information such as personal information of the subscriber 190.

The phone number may be a wired phone number as well as a wireless phone number in the first country. Thus, in an embodiment of the present invention, the subscriber 190 may use the roaming service for not only a wireless phone but also a wired phone.

The call forwarding period means a period during which the subscriber 190^' receives the roaming service in the second country, and the reverse call forwarding period means a period during which the subscriber 190 receives a reverse roaming service in the first country. Herein, the reverse roaming service is defined as a service allowing the subscriber 190 to receive a call incoming at a second-country roaming number through a first-country phone number after returning to the first country from the second country.

Although the subscriber 190 inputs the subscriber information online by using the first-country communication network 140 in the foregoing description, the subscriber 190 may also input the subscriber information offline. In other words, the subscriber 190 may input the subscriber information offline in a company which operates the bidirectional roaming system 100, or a branch or a business office of the company.

For example, the subscriber 190 may input the subscriber information in a branch or a business office located in an airport of the first country before leaving for the second country, or may input the subscriber information in a branch or a business office located in the second country after arriving at the second country.

The subscriber 190 uses the roaming service in the second country by using a terminal corresponding to a local roaming number. To this end, the subscriber 190 may rent or buy the terminal from a company (or a branch or a business office thereof) which operates the bidirectional roaming system 100 in the first country before leaving for the second country or in the second country after arriving at the second country.

The terminal used by the subscriber 190' in the second country is suitable for the second-country communication network 160 and is preferably, without being limited to, a wireless terminal. Thus, the subscriber 190' may also receive the roaming service in the second country by using a wired phone of the second country.

The information storing unit 119 stores information necessary for providing the bidirectional roaming service, such as the subscriber information received by the transmitting/receiving unit 111, location information and line information, and charge information. The local information includes a local roaming number and a local temporary number.

The line information, which is information of a communication line corresponding to an overseas roaming number, includes an Internet Protocol (IP) of the communication line, state information, etc. The local information, the line information, and the charge information will be described in detail later. The main connection processing unit 113 determines the main temporary number corresponding to the subscriber information, i.e., the phone number in operation S203. In an embodiment of the present invention, the main temporary number preferably uses Direct Inward Dialing (DID). For example, if a line El is used, 300 phone numbers may be assigned for a temporary number, and in this case, 30 persons can communicate at the same time. It can be understood by those of ordinary skill in the art that the main temporary number may also be assigned by using other communication methods as well as DID.

The main connection processing unit 113 determines whether the call forwarding period arrives in operation S205. If the call forwarding period arrives, the main connection processing unit 113 requests a first-country common carrier to perform call forwarding from the phone number to the main temporary number in operation S207 and connects the main temporary number to the local roaming number. After completion of call forwarding, a call incoming at the phone number is automatically forwarded to the main temporary number and then is connected to the local roaming number connected to the main temporary number.

In an embodiment of the present invention, it is preferable that the subscriber 190 be informed of the local roaming number when inputting the subscriber information. Thus, when the subscriber 190 inputs the subscriber information online, the transmitting/receiving unit 111 preferably transmits the local roaming number corresponding to the phone number to the subscriber 190.

The local roaming number is a phone number to be used in the second country where a subscriber is to receive the roaming service. In an embodiment of the present invention, after the arrival of the call forwarding period, the overseas roaming number keeps connected to the corresponding main temporary number at all times by forming a set with the corresponding main temporary number.

While the main temporary number is determined prior to the arrival of the call forwarding period in the foregoing description, it may also be determined after the arrival of the call forwarding period. In this case, the main connection processing unit 113 determines the main temporary number upon the arrival of the call forwarding period, requests call forwarding, and then connects the main temporary number to the local roaming number.

The main communication control unit 115 transmits and receives data to and from the local server 130 through the communication line 120. In an embodiment of the present invention, after the arrival of the call forwarding period, the temporary phone number keeps connected to the local roaming number. Thus, a call made by the caller 180 at the phone number is forwarded to the main temporary number and thus is automatically connected to the local roaming number, thereby performing data transmission/reception between the caller 180 and the subscriber 190^' staying in the second country in operation S209.

Hereinafter, the structure and operation of the main communication control unit 115 will be described with reference to FIG. 1. The main communication control unit 115 transmits and receives data according to an IP of a communication line corresponding to the local roaming number. The main communication control unit 115 generally transmits and receives voice data through the IP corresponding to the local roaming number, but it may also transmit and receive other types of data such as images and Short Message Service (SMS) messages as well as voice data.

Referring back to FIG. 1, the main communication control unit 115 includes a main gateway 1151 and a main gatekeeper 1153 and may further include a reception gateway 1155 and a reception gatekeeper 1157. The main gateway 1151 transmits and receives data to and from the local server 130 through the communication line 120. The main gatekeeper 1153 performs number management for the main gateway 1151.

In an embodiment of the present invention, data being input from outside can be directly received. The reception gateway 1155 receives data being input from outside and the reception gatekeeper 1157 performs number management for the reception gateway 1155. For example, if the subscriber 190' makes an international phone call to the first country by using a terminal corresponding to the local roaming number while staying in the second country, the reception gateway 1155 is connected to the communication line 120 in order to forward the international phone call from the terminal to a reception phone number of the first country, thereby making the international phone call to the first country.

In an embodiment of the present invention, the communication line 120 may be any type of line that can be used for communications between countries, and is preferably one of a Voice over Internet Protocol (VoIP) line, an international phone line, and a Direct Outward Dialing (DOD) line.

For example, when the VoIP line is used for the communication line 120, an Internet IP corresponding to the local roaming number is stored in the information storing unit 119. If the caller 180 requests call connection after the arrival of the call forwarding period, the main communication control unit 115 connects the main gateway 1151 with a local gateway 1331 corresponding to the internet IP through an Internet network. The local gateway 1331 then transmits and receives data to and from the subscriber 190^' through the second-country communication network 160.

The subscriber 190 of the first country leaves for the second country and receives the roaming service in the second country in the foregoing description, and the local gateway 1331 of the local server 130 is used for the roaming service in the second country.

When the subscriber 190' returns to the first country from the second country, a call may income at the local roaming number used in the second country. In an embodiment of the present invention, by using the local server 130, the subscriber 190 can receive the roaming service for a call incoming at the local roaming number after returning to the first country.

Referring back to FIG. 1, the local server 130 includes a local connection processing unit 133 and a local communication control unit 131. Hereinafter, an operation allowing a subscriber to receive a roaming service for a call incoming at a local roaming number after returning to a first country will be described with reference to FIGS. 1 and 2.

The local connection processing unit 133 determines whether the reverse call forwarding period arrives in operation S211. In case of the arrival of the reverse call forwarding period, the local connection processing unit 133 determines a local temporary number corresponding to the local roaming number in operation S213, requests a second-country common carrier to perform call forwarding from the local roaming number to the local temporary number in operation S215, and connects the local temporary number to the phone number of the first country. After completion of reverse call forwarding, a call incoming at the local roaming number is forwarded to the local temporary number and thus is automatically connected to the phone number connected to the local temporary number.

Although the local temporary number is determined after the arrival of the reverse call forwarding time in the foregoing description, it may also be determined prior to the arrival of the reverse call forwarding time. For example, the main server 110 provides information indicating that the subscriber 190 desires to receive the reverse roaming service, and the local connection processing unit 113 may determine the local temporary number after receiving the information.

The local communication control unit 131 transmits and receives data to and from the main server 110 through the communication line 120. In an embodiment of the present invention, after the arrival of the reverse call forwarding period, the local temporary number keeps connected to the phone number. Thus, a call made by the caller 170 at the local roaming number is forwarded to the local temporary number and thus is automatically connected to the phone number, thereby performing data transmission/reception between the caller 170 and the subscriber 190 being in the first country in operation S217. The local communication control unit 131 generally transmits and receives voice data through the communication line 120, but it may also transmit and receive other types of data such as images and SMS messages as well as voice data.

Referring back to FIG. 1, the local communication control unit 131 includes the local gateway 1331 and the local gatekeeper 1333. The local gateway 1311 transmits and receives data to and from the main server 110 through the communication line 120. The local gatekeeper 1333 performs number management for the local gateway 1331.

The main server 110 of the bidirectional roaming system 100 further includes the charge processing unit 117 for charging the subscribers 190 and 190^' for the bidirectional roaming service. The charge processing unit 117 calculates a charge corresponding to a communication time in real time. Charge information such as a communication time and a charge corresponding to the communication time is stored in the information storing unit 119. The charge processing unit 117 charges the subscriber 190 the calculated charge separately at every predetermined time or collectively at a time upon cancellation of the bidirectional roaming service. When the subscriber 190 does not desire to continue receiving the roaming service, the subscriber 190 may cancel the roaming service in a similar mariner to when applying for the roaming service. In other words, the subscriber 190 may access the main server 110 online through the first-country communication network 140 and cancel the roaming service according to a guide screen or ARS voice. In case of renting a terminal for the roaming service, the subscriber 190 has to return the terminal to a company which operates the bidirectional roaming system 100 or a branch or a business office thereof when cancelling the roaming service. The embodiment of the present invention has been disclosed in the drawings and specification. Although specific terms are used in the foregoing description, these terms are merely for purposes of illustration and are not intended to define or limit the scope of the invention. Accordingly, it will be understood by one of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

[Industrial Applicability] The present invention can be used in technical fields associated with roaming of portable terminals.

Claims

[CLAIMS] [Claim 1]

A bidirectional roaming system for executing a bidirectional roaming service between a first country and at least one second country which is different from the first country, the bidirectional roaming system comprising: a main server installed in the first country, determining a main temporary number corresponding to a phone number of a subscriber of the first country, and connecting the main temporary number to which a call incoming at the phone number is forwarded to a local roaming number connected to the main temporary number upon arrival of a call forwarding period in order to transmit and receive data through a communication line corresponding to the local roaming number; and a local server installed in the second country, determining a local temporary number corresponding to the local roaming number, and connecting the local temporary number to which a call incoming at the local roaming number is forwarded to the phone number connected to the local temporary number upon arrival of a reverse call forwarding period in order to transmit and receive data through the communication line.

[Claim 2]

The bidirectional roaming system of claim 1, wherein the main server comprises^ a transmitting/receiving unit receiving subscriber information including the phone number, the call forwarding period, and the reverse call forwarding period; a main connection processing unit determining the main temporary number corresponding to the subscriber information, requesting call forwarding from the phone number to the main temporary number upon arrival of the call forwarding period, and connecting the main temporary number to the local roaming number; a main communication control unit transmitting and receiving data to and from the local server through the communication line; and an information storing unit storing the subscriber information, local information including the local roaming number and the local temporary number, and line information of the communication line.

[Claim 3]

The bidirectional roaming system of claim 2, wherein the transmitting/receiving unit receives the subscriber information through the Internet or a wired/wireless phone and transmits the local roaming number corresponding to the phone number to the subscriber.

[Claim 4]

The bidirectional roaming system of claim 2, wherein the main communication control unit comprises: a main gateway transmitting and receiving data to and from the local server through the communication line; and a main gatekeeper performing number management for the main gateway.

[Claim 5] The bidirectional roaming system of claim 4, wherein the main communication control unit further comprises: a reception gateway receiving data being input from outside; and a reception gatekeeper performing number management for the reception gateway.

[Claim 6]

The bidirectional roaming system of claim 1, wherein the local server comprises: a local connection processing unit determining the local temporary number corresponding to the local roaming number, requesting call forwarding from the local roaming number to the local temporary number upon arrival of the reverse call forwarding period, and connecting the local temporary number to the phone number connected to the local temporary number; and a local communication control unit transmitting and receiving data to and from the main server through the communication line.

[Claim 7]

The bidirectional roaming system of claim 6, wherein the local communication control unit comprises : a local gateway transmitting and receiving data to and from the main server through the communication line; and a local gatekeeper performing number management for the local gateway.

[Claim 8] The bidirectional roaming system of claim 1, wherein the main temporary number and/or the local temporary number use Direct Inward Dialing (DID). [Claim 9]

The bidirectional roaming system of claim 1, wherein the communication line is one of a Voice over Internet Protocol (VoIP) line, an international phone line, and a Direct Outward Dialing (DOD) line. [Claim 10]

A bidirectional roaming method for executing a bidirectional roaming service between a first country and at least one second country which is different from the first country, the bidirectional roaming method comprising: receiving subscriber information of a subscriber of the first country, the subscriber information including a phone number, a call forwarding period, and a reverse call forwarding period; determining a main temporary number corresponding to the subscriber information; connecting the main temporary number to which a call incoming at the phone number is forwarded to a local roaming number upon arrival of the call forwarding period in order to transmit and receive data through a communication line corresponding to the local roaming number; and determining a local temporary number corresponding to the local roaming number and connecting the local temporary number to which a call incoming at the local roaming number is forwarded to the phone number connected to the local temporary number upon arrival of the reverse call forwarding period in order to transmit and receive data through the communication line. [Claim 111

The bidirectional roaming method of claim 10, wherein the receiving of the subscriber information comprises: receiving the subscriber information by using the Internet or a wired/wireless phone; and transmitting the local roaming number corresponding to the phone number to the subscriber.

[Claim 12]

The bidirectional roaming method of claim 10, wherein the transmitting and receiving of the data upon arrival of the call forwarding period comprises: requesting call forwarding from the phone number to the main temporary number and connecting the main temporary number to the local roaming number; and transmitting and receiving data to and from the local server through the communication line.

[Claim 13] The bidirectional roaming method of claim 10, wherein the transmitting and receiving of the data upon arrival of the reverse call forwarding period comprises: requesting call forwarding from the local roaming number to the local temporary number and connecting the local temporary number to the phone number connected to the local temporary number; and transmitting and receiving data to and from the main server through the communication line.

[Claim 14] The bidirectional roaming method of claim 10, wherein the main temporary number and/or the local temporary number use Direct Inward Dialing (DID). [Claim 15]

The bidirectional roaming method of claim 10, wherein the communication line is one of a Voice over Internet Protocol (VoIP) line, an international phone line, and a Direct Outward Dialing (DOD) line.