WO2009084767A1

WO2009084767A1 - Method and circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic ip addresses, and system and method for providing free video communication service

Info

Publication number: WO2009084767A1
Application number: PCT/KR2008/001016
Authority: WO
Inventors: Hwang-Eui Lee; Yong-Su Jeon; Hyun-Woo Choi; Jung-Hwan Jang; Ho-Ju Lee; Chi-Ho Won
Original assignee: Rinnai Korea Corp.
Priority date: 2007-12-27
Filing date: 2008-02-21
Publication date: 2009-07-09

Abstract

Disclosed herein are a method and circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, and a system and method for providing free video communication service. The method of registering addresses and maintaining connection includes the steps of (A) a system A connecting to a system B over a Public Switched Telephone Network (PSTN), (B) the system B transmitting an IP address to the system A over the PSTN in a DTMF signal form; (C) the system A storing and registering the IP address of the system B together with an ID of the system B; (D) the system A connecting to the system B over the Internet using the registered IP information of the system B and retransmitting system information data to the system B; and (E) the system B registering the system information data.

Description

Description METHOD AND CIRCUIT FOR REGISTERING ADDRESSES

AND MAINTAINING CONNECTION FOR INTERCONNECTION BETWEEN SYSTEMS BASED ON DYNAMIC IP ADDRESSES, AND SYSTEM AND METHOD FOR PROVIDING

FREE VIDEO COMMUNICATION SERVICE Technical Field

[ 1 ] The present invention relates to a process of registration and method of maintenance of connection for interconnection between systems connected to the Internet based on dynamic Internet Protocol (IP) addresses and, more particularly, to a method and circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, in which an ARS call is made using the telephone number of a counterpart to be registered over an existing Public Switched Telephone Network (PSTN), and network connection is set up through direct registration/automatic registration processes depending on whether the counterpart approves the registration.

[2] Furthermore, the present invention relates to a system and method for providing free video communication service between systems based on dynamic IP addresses, in which users can use free video communication service in video terminals having dynamic IP addresses regardless of their areas, distances and locations, between homes having home networks, using IDs previously registered with video terminal devices, such as home network video telephones, Wallpads, Webpads, interphones, digital photo frames, IPTV and Personal Computers (PCs), without requiring a complicated procedure of requesting the IP information of a counterpart from a specific service server in order to know the ID address of the counterpart who desires to use the free video communication service. Background Art

[3] All network equipment connected to the Internet has unique TCP/IP addresses, and this network equipment can be accessed using the IP addresses from external networks, and then Internet service is used through the network equipment. IP addresses necessary to access the Internet are classified into static IP addresses and dynamic IP addresses. Static IP addresses are advantageous in that access can be made using the static IP addresses anywhere and anytime because IP addresses assigned by an Internet Service Provider (ISP) are not changed, but are disadvantageous in that a high price must be paid for the use of the static IP addresses. With regard to dynamic IP address, IP addresses assigned by an ISP may not be fixed, but may change. Accordingly, the dynamic IP addresses are disadvantageous in that direct access cannot be made from external remote places because variable IP addresses cannot be known from external remote places. In order to solve these problems, a method of providing a specific relay server, including a database (DB) capable of storing unique ID information, such as the unique IDs and assigned IP addresses of systems connected to the Internet using dynamic IP addresses, and, when an access request is made from an external remote place, searching for the ID of a relevant system and connecting to a dynamic IP address that is currently assigned and used for access, is currently the most widely used method.

[4] FIG. 1 is a block diagram showing a network configuration in which the Dynamic

Host Configuration Protocol (DHCP) is applied to a conventional embedded system, which is disclosed in Korean Patent No. 10-0721341.

[5] Referring to FIG. 1, a conventional network includes an embedded system 40, a

DHCP server 50, user terminals 60 and a management server 70, which are connected to the Internet. The embedded system 40 includes embedded terminals 41, which provide respective specialized services. Each of the embedded terminals 41 is assigned a dynamic IP address by the DHCP server 50 over the Internet, accesses the Internet using the assigned IP address, and provides various services to the user terminals 60.

[6] The DHCP server 50 assigns respective dynamic IP addresses to the embedded terminals 41 of the embedded system 40 so that the embedded terminals 41 can access the Internet and provide services. The management server 70 manages IP address information, which is assigned to the embedded terminals 41 by the DHCP server 50. In the case in which an embedded terminal 41 is assigned a new IP address by the DHCP server 50, such as the case in which the power or Internet connection of the embedded terminal 41 is turned on or set up again after being turned off or released, the management server 70 is notified thereof in the form of an event, and stores and manages the new IP address.

[7] The management server 70 includes a web server module 71, a subscriber module

72, an embedded system management module 73, a DB 74 and a log module 75. The web server module 71 is a web service-related module that can access the Internet and control and manage the management server 70. The subscriber module 72 manages subscriber information, which is used for the use of the embedded system 40. That is, if the subscriber module 72 receives a request from the user terminal 60 that accesses the embedded terminal 41 and desires to use service, the subscriber module 72 determines whether a relevant user is a service subscriber and provides the IP address of the embedded terminal 41 to the user terminal 60. The embedded system management module 73 enables the management of the embedded system 40 from a remote place and processes events attributable to the addition or removal of an embedded terminal 41 or the like. The DB 74 includes a terminal mapping table for storing subscriber information and IP address information assigned to the embedded terminals 41.

[8] In this conventional network configuration, a separate relay server for connecting terminals having dynamic IPs is required, and high construction costs for constructing a database for processing a number of subscribers is necessary in order to install the relay server. This method is a method that is economically unviable or impractical when a small number of users, rather than a large number of users, is interconnected and uses Internet services.

[9] Meanwhile, in the case in which connection is set up through a dedicated line, a client is always assigned a static IP, and can be accessed from the outside through the static IP. In contrast, in the case in which the client is connected using a general dynamic IP address (ADSL, PSTN, PPP, etc.), the client is assigned a new IP address at the time of connection, and thus the dynamic IP is not known, so that it is difficult to access the client from the outside.

[10] Accordingly, in a home network constructed based on static IP addresses, IP addresses can be mutually known in advance, and connection between the IP addresses can be easily set up if the connection is allowed between the IP addresses in terms of security.

[11] However, in order for a general user to construct a home network and use a static IP so as to use video communication, high costs are incurred, and thus there is no validity from economical or practical viewpoints. In a home network system constructed based on dynamic IP addresses, interconnection is not easy without the use of a specific service server that provides information about changed IPs between two parties because the two parties cannot otherwise know the changed IPs.

[12] FIG. 2 is a diagram showing a home network system constructed based on conventional dynamic IP addresses.

[13] Referring to FIG. 2, the conventional network system involves a complicated process, in which a terminal A 51 is assigned a dynamic IP address by an Internet Service Provider (ISP) server A 50, the ID and dynamic IP address of the terminal A 51 are stored in a service server 70, and, when a client 61 having a dynamic IP address assigned by another ISP server B 60 desires to access the counterpart terminal A 51, the client 61 requests the changed dynamic IP address information of the counterpart terminal A 51 from the service server 70 and accesses the counterpart terminal A 51 using the dynamic IP address information of the terminal A 51 received from the service server 70.

[14] Such a conventional network configuration requires a separate service server for connecting terminals having dynamic IPs. In order to install the service server, high costs for constructing a database for processing a plurality of accessors are required.

This is an economically inviable or impractical method for interconnection between a small number of users, rather than a large number of users, or for the use of Internet service.

Disclosure of Invention

Technical Problem

[15] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method and circuit unit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, which provide Internet service between users who access the Internet using dynamic IP addresses without installing a specific relay server.

[16] Another object of the present invention is to provide a method in which dynamic IP addresses, assigned and used in general homes, are recognized as static IP addresses even without the use of an expensive specific relay server.

[17] A further object of the present invention is to provide a system and method for providing free video communication service between systems based on dynamic IP addresses, in which, in a home network system constructed based on dynamic IP addresses, free video communication service is made available using only a send button over a PSTN through the synchronization of dynamic IP addresses without using a specific server. Technical Solution

[18] In order to accomplish the above objects, the present invention provides A method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses for data communication between systems connected to an Internet based on dynamic IP addresses, the method including the steps of (A) a system A connecting to a system B over a Public Switched Telephone Network (PSTN) in order to register Internet Protocol (IP) addresses;

[19] (B) the system B transmitting an IP address to the system A over the PSTN in a

DTMF signal form; (C) the system A storing and registering the IP address of the system B, which is received from the system B in a DTMF signal form, together with an ID of the system B;

[20] (D) the system A connecting to the system B over the Internet using the registered IP information of the system B and retransmitting system information data, including an ID and IP address information of the system A, to the system B; and (E) the system B registering the system information data retransmitted from the system A. [21] Preferably, the step (B) may be the step of directly receiving the IP address of the system B from a user through a terminal and transmitting the input IP address to the system A using a DTMF generator.

[22] Furthermore, the step (B) may include the steps of the system B, connected to the

Internet, fetching current IP information, assigned by an Internet Service Provider (ISP), using an IP information check unit; and a DTMF transmission unit transmitting the current IP information to the system A using a DTMF generator in a DTMF signal form.

[23] The method may further includes the steps of, when the IP address of the system A or the system B is changed, a system, having a changed IP address, transmitting system information data, including its own ID and the changed IP address, to a counterpart system using the IP address of the counterpart system, which is stored therein; the counterpart system receiving the system information data from the system having the changed IP address; and the counterpart system performing analysis by comparing the system information data, received from the system having the changed IP address, with previously stored data, and updating information.

[24] Furthermore, the method may further include the steps of, when interconnection between the system A and the system B is released, any one system transmitting a message with reference to IP addresses of a group, which have been previously registered; when connection over the Internet cannot be set up due to a changed IP address of a counterpart system, transmitting a DTMF signal to the counterpart system, which does not make a response, over the PSTN; and the counterpart system, which has received the DTMF signal, retransmitting the changed IP address information over the PSTN in a DTMF signal form.

[25] Furthermore, the present invention provides a circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, the circuit including a PSTN circuit for providing data transmission over a PSTN in order to provide data communication between systems connected over an Internet based on dynamic IP addresses; a DTMF transmission unit for generating IP address information of the systems in a DTMF signal form; a DTMF reception unit for receiving the DTMF signal transmitted from a counterpart system; a memory unit for storing an ID and IP address of a counterpart system, which have been received through the DTMF reception unit, and its own ID and IP address; an Internet connection circuit unit for retransmitting system information data, including its own ID and IP address information, to the counterpart system based on the IP address information received through the DTMF reception unit; and a control circuit unit for controlling operation of the PSTN circuit, the DTMF transmission unit, the DTMF reception unit, the memory unit and the Internet connection circuit unit. [26] Preferably, the DTMF transmission unit may directly receive the IP address of the counterpart system from a user through a terminal and transmit the IP address to the counterpart system in a DTMF signal form.

[27] Furthermore, the DTMF transmission unit may fetch the IP address information of the system, which is assigned by an ISP, using an IP information check unit and transmit the IP address information to the counterpart system in a DTMF signal form.

[28] Furthermore, the systems may be terminals that include video telephones, Wallpads,

Webpads, interphones, digital photo frames, IPTVs and Personal Computers (PCs), have IP addresses, and can transmit and receive signals in conjunction with the Internet.

[29] Furthermore, the present invention provides a system for providing free video communication service between systems based on dynamic IP addresses, the system including a first video terminal for transmitting video data for video communication and storing an assigned ID and dynamic IP address; a first gateway for transmitting the video data, transmitted from the first video terminal, over an Internet; a second gateway for receiving the video data transmitted over the Internet and transmitting the ID and dynamic IP address information of the first video terminal, which has been transmitted from the first gateway, over a PSTN; a second video terminal for outputting the video data received through the second gateway and storing the transmitted ID and IP address of the first video terminal; and an ISP server for assigning dynamic IP addresses to the first and second video terminals.

[30] Preferably, when the first video terminal is in operation, the middleware of the first home network gateway may transmit the dynamic IP address information of the first video terminal to a registered user group over the PSTN, and the middleware of the second gateway located on a receiving side for the video data may transmit the ID and IP address information of the first video terminal, which have been transmitted from the first gateway over the PSTN, to the second video terminal.

[31] Furthermore, when the IP address of the first video terminal is changed, the middleware of the first gateway may transmit the changed IP address information of the first video terminal to a registered user group over the PSTN and update the IP address information.

[32] Furthermore, the present invention provides a method of providing free video communication service between systems based on dynamic IP addresses, the method including the step of registering an IP address of a second video terminal with a first video terminal over a PSTN; a first gateway middleware for a home network, which is connected to the first video terminal, checking whether an IP address assigned to the first gateway has been changed; the first gateway middleware periodically determining whether the IP address assigned to the first gateway has been changed; when the IP address of the first gateway has been changed, transmitting update data of the first gateway to an ID of the second video terminal, which is stored in the first video terminal connected to the first gateway, over the PSTN; and a second gateway updating and storing the update data of the first gateway, which has been transmitted.

[33] Preferably, the step of registering the IP address of the second video terminal with the first video terminal may include receiving and registering IP address information of a counterpart over the PSTN.

[34] Furthermore, the step of registering the IP address of the second video terminal with the first video terminal may include, when the IP address information of the second video terminal is already known, registering the IP address information of the second video terminal using a GUI of the first video terminal.

[35] Furthermore, the update data may include a flag value indicative of whether the IP address of the first gateway has been changed, an ID (a central office line telephone number) of the first gateway, the changed IP address information of the first gateway, and a flag value indicative of whether the changed IP address of the first gateway has already been registered.

[36] Furthermore, the present invention provides a method of providing free video communication service between systems based on dynamic IP addresses, the method including the steps of a first gateway checking a state of connection with a gateway group that has been previously registered, in a booting process after power-on; when there is no response from a second gateway, transmitting a DTMF signal, requesting changed IP address information, to the second gateway over a PSTN; checking IP address information of the second gateway, which is currently assigned; the second gateway transmitting its current IP address to the first gateway as a DTMF signal; the first gateway changing and storing changed IP address information of the second gateway, which has been transmitted from the second gateway, in an existing stored data region; the first gateway transmitting address information, including its own IP, to the second gateway over an Internet using the stored IP address information of the second gateway; and the second video terminal registering the address information of the first gateway, including the IP, which has been received from the first gateway.

[37] Preferably, the step of requesting the DTMF signal, requesting the changed IP address information, to the second gateway over the PSTN may be the step of an ARS of the first gateway transmitting a specific DTMF signal according to a guidance announcement output from the second gateway and requesting the current IP information of the second gateway.

[38] Furthermore, the present invention provides a method of providing free video communication service between systems based on dynamic IP addresses, the method including the step of a first video terminal transmitting a free communication service request signal to a second video terminal using previously registered IP address information; the second video terminal, which has received the free communication service request signal, generating a request event so that a user can be made aware of reception of the request signal; and the second video terminal receiving approval of video communication service from the user, connecting to the first video terminal over an Internet and providing the video communication service to the first video terminal.

[39]

[40] As described above, the present invention has an advantage in that it is not necessary to assign expensive static IP addresses in order to realize network connection between systems and the effect in which connection is set up as if the connection were set up using static IPs can be accomplished without using an expensive specific server in order to realize network connection between systems even on the basis of dynamic IP addresses used in general homes. Using the above advantages, various Internet services, such as video communication or data transmission, which was available only when an expensive separate server or a video transmission system was provided, can be used free of charge.

[41] Furthermore, the present invention can provide video communication service to homes, in which dynamic IP address-based home networks are constructed, free of charge without incurring additional expenses through a predetermined registration procedure without regional or spatial limitations.

[42] These economical effects can play a role in promoting the home network industry, which targets existing (already built)) homes, rather than newly built homes, and can provide another business model that can replace the existing video telephone market, in which expenses are incurred, because additional expenses are not incurred. Brief Description of the Drawings

[43] FIG. 1 is a block diagram showing a network configuration in which DHCP is applied to a conventional embedded system, which is disclosed in Korean Patent No. 10-0721341;

[44] FIG. 2 is a diagram showing a home network system constructed based on conventional dynamic IP addresses;

[45] FIG. 3 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a preferred embodiment of the present invention;

[46] FIG. 4 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to another preferred embodiment of the present invention;

[47] FIG. 5 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to still another preferred embodiment of the present invention;

[48] FIG. 6 is a view showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a further preferred embodiment of the present invention;

[49] FIG. 7 is a diagram showing a circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a preferred embodiment of the present invention;

[50] FIG. 8 is a diagram showing a system for providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention;

[51] FIG. 9 is a flowchart showing an IP information synchronization process in a method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention;

[52] FIG. 10 is a flowchart showing a re-registration process in the method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention; and

[53] FIG. 11 is a flowchart showing a method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention. Best Mode for Carrying Out the Invention

[54] In order to fully understand the advantages of the present invention, the operational advantages of the present invention and the objects accomplished through the practice of the present invention, reference should be made to the accompanying drawings provided to illustrate preferred embodiments of the present invention, and the content illustrated in the accompanying drawings.

[55] The present invention will be described in detail through descriptions of the preferred embodiments with reference to the accompanying drawings. The same reference numbers, present in respective drawings, designate the same elements. FIG. 3 is a view showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[56] Referring to FIG. 3, the present invention is characterized in that it uses an existing

PSTN. A first address registration process and connection maintenance method using the PSTN between systems will be described below.

[57] First, a system A makes an ARS call to a counterpart system B, which the system A desires to first register. If the call is connected, the counterpart system B may determine whether to register an address. For example, the system B may select '1. registration, and 2. rejection¹ in response to ARS voice guidance. In the present invention, a "direct registration method" and an "automatic registration method" are presented as examples of the types of registration methods. The "automatic registration method" will be described in detail later with reference to FIG. 3.

[58] The direct registration method starts to be performed in such a way that, when an

ARS registration request call is received, the system B selects " 1. registration" and then selects a button relevant to the direct registration of "direct registration/automatic registration" after the selection. Assuming that the IP address through which the system B makes access is "221.254.177.67," the direct registration method includes a transmission step SlOO of the system B receiving an IP address, such as '221*254*177*67#', from a user through a terminal and transmitting the received IP address to the system A using a DTMF generator, a reception step Sl 10 of the system A, which made the registration request call, interpreting a DTMF signal, received from the system B, using a DTMF receiver and storing the IP information of the system B together with the unique ID (central office line telephone number) of the system B, which has been stored in the system A, a step S 120 of the system A making access over the Internet and retransmitting system information data, including data fields, such as the current unique ID (a central office line telephone number) and IP information of the system A, to the system B, using the registered IP information of the system B, and a re-reception step S130 of the system B registering the system information data retransmitted from the system A, which made the registration request.

[59] FIG. 4 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to another preferred embodiment of the present invention.

[60] Referring to FIG. 4, the automatic registration method starts to be performed in such a way that, when an ARS registration request call is received from a system A, a system B selects "1. registration" and then selects a button corresponding to automatic registration from a menu, such as "direct registration/automatic registration."

[61] When the system B releases call connection after selecting "automatic registration," the PSTN temporarily maintains a hook-on state. Thereafter, the system B selects an automatic registration button connected to an Internet line, and thus the automatic registration process is performed.

[62] The automatic registration process will be described in greater detail. The automatic registration process includes an automatic transmission step S200 of the system B, which is connected to the Internet, fetching current IP information, assigned by an ISP, using an IP information check unit and a DTMF transmission unit transmitting the current IP information to the system A using a DTMF generator in the form of a DTMF signal, a reception step S210 of the system A, which made the registration request call, interpreting the DTMF signal, received from the system B, using a DTMF receiver and storing the IP information of the system B together with the unique ID (central office line telephone number) of the system B, which is stored in the system A, a step S220 of the system A making access over the Internet and retransmitting system information data, including data fields, such as the current unique ID (a central office line telephone number) and IP information of the system A, to the system B, using the registered IP information of the system B, and a re-reception step S230 of the system B registering the system information data, retransmitted from the system A, which made the registration request.

[63] A method of, when the ID and IP address of a counterpart system are known, directly registering the ID and IP address of the counterpart system, the registration of which is desired, on a system using a GUI registration window may be used as a method of registering the IP address of a system with another system without using the above- disclosed PSTN.

[64] Furthermore, registration may be made by directly inputting the ID and IP address of a counterpart system using a 'register' program in a PC connected to a system through an internal IP address.

[65] When the above-described first registration process is performed, IP information is registered with the system A and the system B and Internet services can be used even without using a relay server.

[66] FIG. 5 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to still another preferred embodiment of the present invention.

[67] Referring to FIG. 5, another aspect of the present invention resides in the fact that, even if the IP information of any one system is changed, the IP information check unit does not check the changed IP information and update a relevant ID and IP information in a relay server, but a system having the changed IP information can maintain connection by collectively transmitting system information data, such as the unique ID and changed IP address of the system, to respective IP addresses within a group, which has been stored in the system, over the Internet. For example, assuming that the IP address of a system A has been changed, connection is maintained through an IP information transmission step S300 of the system A transmitting its own unique ID and the changed IP address to a system B using an IP address of the system B, which has been stored in the system A, an IP information reception step S310 of the system B receiving system information data from the system A having the changed IP address, and an IP information change step S320 of the system B updating information by comparing the system information data, received from the system A, with information previously stored in a DB. This is referred to as 'a data synchronization process.'

[68] Since the above-described series of steps is collectively performed when an IP address is changed, systems registered with each other are always connected over the Internet, regardless of whether IP addresses assigned by an ISP are static IP addresses or dynamic IP addresses, so that the systems can use Internet services, such as data transmission, file transmission and video transmission, anywhere and anytime.

[69] FIG. 6 is a diagram showing a method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a further preferred embodiment of the present invention.

[70] Referring to FIG. 6, in the case in which there is no response from a counterpart system during an IP information data synchronization process between specific systems, or a synchronization process between specific systems fails, a disconnected system automatically performs a re-registration process.

[71] The automatic re-registration process is a connection-maintaining process that is performed through, assuming that a system A is disconnected, a step S400 of transmitting a message with reference to the IP addresses of a group, which has been previously registered, in a booting process, a step S410 of, when connection over the Internet cannot be set up due to a change in IP address or the like, attempting an ARS call connection to a counterpart system B, which does not respond, over the PSTN, a step S420 of, when the call is connected to the system B, the system A transmitting a specific DTMF signal (for example, No. 0), and a step S430 of the system B, which receives the specific DTMF signal, retransmitting changed IP address information to the system A using a DTMF signal.

[72] Since the above process for maintaining interconnection is always performed between systems, connection can be set up again and maintained when power is turned off or connection is released due to an unexpected situation.

[73] FIG. 7 is a diagram showing a circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[74] Referring to FIG. 7, a circuit, mounted in a system and adapted to register addresses and maintain connection between systems, includes a PSTN circuit 100 for performing ARS call connection for data communication between systems connected over the Internet using dynamic IP addresses, a DTMF transmission unit 110 operating as a DTMF generator for generating a DTMF signal for IP address information directly input by a user during a direct registration process and a DTMF signal for IP address information found in a system during an automatic registration process, a DTMF reception unit 120 operating as a DTMF receiver for receiving transmitted DTMF signals, a memory unit 130 for storing the ID and IP address of a counterpart system, received through the DTMF reception unit 120, and the ID and IP address of the present system, an Internet connection circuit unit 140 for retransmitting system information data, such as the ID and IP address information of the present system, using the IP address information received through the DTMF reception unit 120, and a control circuit unit 150 for controlling the constituent elements.

[75] It is noted that the above-described system is based on a concept including any terminals, such as video telephones, Wallpads, Webpads, interphones, digital photo frames, IPTVs, and PCs, which have IP addresses and can transmit or receive signals in conjunction with the Internet.

[76] FIG. 8 is a diagram showing a system for providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[77] Referring to FIG. 8, the system includes a video terminal and gateway for performing video communication in a home network system, which is constructed based on the Internet, in a home.

[78] In greater detail, the system includes a first video terminal 200 for transmitting video data for video communication and storing an assigned ID and dynamic IP address, a first gateway 210 for transmitting video data, transmitted from the video terminal 200, over the Internet, a second gateway 220 for receiving video data transmitted over the Internet and transferring the ID and dynamic IP address information of the first video terminal 200, transmitted from the first gateway 210, over the PSTN, a second video terminal 230 for outputting video data received through the second gateway 220 and storing the transmitted ID and IP address of the first video terminal 200, and an ISP server 240 for assigning dynamic IP addresses to the first and second video terminals 200 and 230.

[79] The operational process of the free video communication service provision system will be described below. When a dynamic IP address-based home network is constructed and the first video terminal 200 operates, the middleware of the first home network gateway 210 transmits the current dynamic IP address information of the video terminal 200 to a registered user group over the PSTN. The middleware of the second gateway 220, located on the receiving side for video data, transmits the ID and IP address information of the first video terminal 200, which have been transmitted from the first gateway 210 over the PSTN, to the second video terminal 230. Thereafter, when the IP address of the first video terminal 200 is changed, the middleware of the first gateway 210 transmits the changed IP address information of the first video terminal 200 to a registered user group over the PSTN, thereby updating the IP address information.

[80] Through this process, connection can always be maintained between video terminals, which have been registered with each other, through IP address synchronization, and users can use free video communication service with counterparts, desiring video communication, merely by using send buttons. That is, the present invention does not require a service server for storing information about dynamic IP addresses, and provides free video communication service regardless of whether static IP addresses or dynamic IP addresses are assigned by an external ISP.

[81] FIG. 9 is a flowchart showing an IP information synchronization process in a method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[82] Referring to FIG. 9, a network is connected by registering the IP address of the second video terminal 230, desiring registration, in advance through a specific registration procedure (a method of automatically registering the IP address information of a counterpart over the PSTN, or a method of directly registering the ID address information of a counterpart using a GUI on a terminal) at step S500. Thereafter, the middleware of the first home network gateway 210 checks whether its own IP address has been changed at step S510. The middleware of the first gateway 210 periodically determines whether the IP address has been changed at step S520. If the IP address has been changed, the middleware of the first gateway 210 transmits update data, such as a flag value ("1"), indicative of whether the IP address of the first gateway 210 has been changed, the ID (a central office line telephone number) of the first gateway 210, the changed IP address of the first gateway 210, and a flag value (" 1"), indicative of whether the changed IP address of the first gateway 210 has already been registered, to a video communication group, stored in the first video terminal 200 connected to the first gateway 210 and configured to include the second video terminal 230, at step S530. The second gateway 220 of the video communication group identifies received update data using the ID and updates relevant information, thereby synchronizing IP information within a group at step S540. If the IP address has not been changed, the middleware of the first gateway 210 returns to the step S510 and then checks whether the IP address has been changed. If IP information synchronization with the first gateway 210 is not performed because the dynamic IP of the second gateway 220 is changed in the case in which the first gateway 210 is powered off in the state in which the first gateway 210 and the second gateway 220 are connected, the first gateway 210 and the second gateway 220 may be disconnected from each other. In order to solve this problem, both the gateways perform a process of checking the state of connection to a group, which has been previously registered, in a booting process after power-on. If there is no response from a counterpart-side gateway in this process, connection is considered to be disconnected and then the re-registration process is performed.

[83] FIG. 10 is a flowchart showing a re-registration process in the method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[84] Referring to FIG. 10, when the first gateway 210, which was powered off, is powered on, a process of checking IP address information is performed on a gateway group, which has been previously registered, in a booting process, and the re-registration process is performed on a counterpart gateway, which does not make a response, in this process at step S600. In greater detail, when the IP address information of any second gateway 220 can be found, the first gateway 210 checks the IP address information of another second gateway 220. When the IP address information of any second gateway 220 cannot be found, the first gateway 210 makes an ARS call to a second gateway 220, which does not respond, using a central office line telephone number at step S610.

[85] This process may be divided into two cases: the case in which a user receives an

ARS signal and the case in which a system receives an ARS signal at step S620.

[86] The first is the case in which, when the first gateway 210 makes an ARS call to a counterpart second video terminal 230, a human answers a call received from the counterpart. In this case, a registration process starts to be performed in such a way that a user presses a 'register¹ button in response to an ARS announcement output through the second video terminal 230 at step S630.

[87] For example, if the ARS announcement "Existing IP information has been changed.

Please hang up and press a 'register' button on the video terminal" is transmitted from the first gateway 210 and output through the second video terminal 230, a user hangs up, presses the 'register' button on the second video terminal 230, and updates IP information between systems.

[88] The second is the case in which, when the first gateway 210 makes an ARS call to the second video terminal 230, the counterpart second gateway 220 answers the call. In this case, an ARS announcement is output from the second gateway 220 to the first gateway 210 at step S640.

[89] An ARS announcement for a home network is output because the second gateway

220 is an ARS associated with a home network system. While this announcement is output, the ARS of the first gateway 210 requests the current IP information of the second gateway 220 by transmitting a specific DTMF signal '*' at step S650.

[90] When the 'register' button is pressed at step S630, or a specific DTMF signal, such as

'*', is received at step S650, the second gateway 220 recognizes an IP information re- registration request and checks the current dynamic IP address information of the second gateway 220 at step S660. After the IP address information is found, the second gateway 220 transmits its own IP address to the first gateway 210 in the form of a DTMF signal at step S670. The first gateway 210 stores the changed IP address in- formation of the second gateway 220, transmitted from the second gateway 220, in an existing data region at step S680. The first gateway 210 transmits data, having the format "a flag indicative of whether an IP address has been changed, an ID (a central office line telephone number), changed IP address information, and a flag indicative of whether the changed IP address has already been registered," to the second gateway 220 using the stored IP address information over the Internet at step S690. The second video terminal 230 registers the ID and address information of the first gateway 210, which have been transmitted from the first gateway 210, at step S700.

[91] The above process is performed in the same manner in all systems when IP information synchronization fails after IP information has been changed in any specific system. Accordingly, even when power is turned off in a specific system, connection is automatically set up again at the time of rebooting, so that connection is not released between systems that have been registered with each other.

[92] FIG. 11 is a flowchart showing a method of providing free video communication service between systems based on dynamic IP addresses according to a preferred embodiment of the present invention.

[93] Referring to FIG. 11, a free communication service request signal is transmitted from the first video terminal 200 to the second video terminal 230 using the previously registered IP address information of the second video terminal 230 at step S800. The second video terminal 230, which has received the free communication service request signal, generates a request event so that a user can be made aware of the reception of the request signal at step S810. If the user of the second video terminal 230 approves video communication service at step S820, the video communication service is provided at step S830. If the user of the second video terminal 230 does not approve the video communication service, a connection failure message is output at step S840.

[94] Since IP addresses are always synchronized between the first gateway 210 and the second gateway 220, a process of requesting IP information from a specific server for storing IP information when free communication service is used is not necessary. Video communication service can be easily provided even on a dynamic IP basis in such a way as to select a counterpart name and press a send button, as in the use of a common telephone.

[95] Although the present invention has been described with reference to the embodiments illustrated in the accompanying drawings, the embodiments are only illustrative. Those skilled in the art will appreciate that various modifications and other equivalent embodiments can be made based on the embodiments. Accordingly, the true technical scope of the present invention should be defined by the technical spirit of the attached claims.

Claims

[1] A method of registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses for data communication between systems connected to an Internet based on dynamic IP addresses, the method comprising the steps of:

(A) a system A connecting to a system B over a Public Switched Telephone Network (PSTN) in order to register Internet Protocol (IP) addresses;

(B) the system B transmitting an IP address to the system A over the PSTN in a DTMF signal form;

(C) the system A storing and registering the IP address of the system B, which is received from the system B in a DTMF signal form, together with an ID of the system B;

(D) the system A connecting to the system B over the Internet using the registered IP information of the system B and retransmitting system information data, including an ID and IP address information of the system A, to the system B; and

(E) the system B registering the system information data retransmitted from the system A.

[2] The method as set forth in claim 1, wherein the step (B) is the step of directly receiving the IP address of the system B from a user through a terminal and transmitting the input IP address to the system A using a DTMF generator.

[3] The method as set forth in claim 1, wherein the step (B) comprises the steps of: the system B, connected to the Internet, fetching current IP information, assigned by an Internet Service Provider (ISP), using an IP information check unit; and a DTMF transmission unit transmitting the current IP information to the system A using a DTMF generator in a DTMF signal form.

[4] The method as set forth in claim 1 , further comprising the steps of: when the IP address of the system A or the system B is changed, a system, having a changed IP address, transmitting system information data, including its own ID and the changed IP address, to a counterpart system using the IP address of the counterpart system, which is stored therein; the counterpart system receiving the system information data from the system having the changed IP address; and the counterpart system performing analysis by comparing the system information data, received from the system having the changed IP address, with previously stored data, and updating information.

[5] The method as set forth in claim 1, further comprising the steps of: when interconnection between the system A and the system B is released, any one system transmitting a message with reference to IP addresses of a group, which have been previously registered; when connection over the Internet cannot be set up due to a changed IP address of a counterpart system, transmitting a DTMF signal to the counterpart system, which does not make a response, over the PSTN; and the counterpart system, which has received the DTMF signal, retransmitting the changed IP address information over the PSTN in a DTMF signal form.

[6] A circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, the circuit comprising a PSTN circuit for providing data transmission over a PSTN in order to provide data communication between systems connected over an Internet based on dynamic IP addresses; a DTMF transmission unit for generating IP address information of the systems in a DTMF signal form; a DTMF reception unit for receiving the DTMF signal transmitted from a counterpart system; a memory unit for storing an ID and IP address of a counterpart system, which have been received through the DTMF reception unit, and its own ID and IP address; an Internet connection circuit unit for retransmitting system information data, including its own ID and IP address information, to the counterpart system based on the IP address information received through the DTMF reception unit; and a control circuit unit for controlling operation of the PSTN circuit, the DTMF transmission unit, the DTMF reception unit, the memory unit and the Internet connection circuit unit.

[7] The circuit as set forth in claim 6, wherein the DTMF transmission unit directly receives the IP address of the counterpart system from a user through a terminal and transmits the IP address to the counterpart system in a DTMF signal form.

[8] The circuit as set forth in claim 6, wherein the DTMF transmission unit fetches the IP address information of the system, which is assigned by an ISP, using an IP information check unit and transmits the IP address information to the counterpart system in a DTMF signal form.

[9] The circuit as set forth in claim 6, wherein the systems are terminals that include video telephones, Wallpads, Webpads, interphones, digital photo frames, IPTVs and Personal Computers (PCs), have IP addresses, and can transmit and receive signals in conjunction with the Internet.

[10] A system for providing free video communication service between systems based on dynamic IP addresses, the system comprising a first video terminal for transmitting video data for video communication and storing an assigned ID and dynamic IP address; a first gateway for transmitting the video data, transmitted from the first video terminal, over an Internet; a second gateway for receiving the video data transmitted over the Internet and transmitting the ID and dynamic IP address information of the first video terminal, which has been transmitted from the first gateway, over a PSTN; a second video terminal for outputting the video data received through the second gateway and storing the transmitted ID and IP address of the first video terminal; and an ISP server for assigning dynamic IP addresses to the first and second video terminals.

[11] The system as set forth in claim 10, wherein, when the first video terminal is in operation, middleware of the first home network gateway transmits the dynamic IP address information of the first video terminal to a registered user group over the PSTN, and middleware of the second gateway located on a receiving side for the video data transmits the ID and IP address information of the first video terminal, which have been transmitted from the first gateway over the PSTN, to the second video terminal.

[12] The system as set forth in claim 10, wherein, when the IP address of the first video terminal is changed, middleware of the first gateway transmits the changed IP address information of the first video terminal to a registered user group over the PSTN and updates the IP address information.

[13] A method of providing free video communication service between systems based on dynamic IP addresses, the method comprising the step of registering an IP address of a second video terminal with a first video terminal over a PSTN; a first gateway middleware for a home network, which is connected to the first video terminal, checking whether an IP address assigned to the first gateway has been changed; the first gateway middleware periodically determining whether the IP address assigned to the first gateway has been changed; when the IP address of the first gateway has been changed, transmitting update data of the first gateway to an ID of the second video terminal, which is stored in the first video terminal connected to the first gateway, over the PSTN; and a second gateway updating and storing the update data of the first gateway, which has been transmitted.

[14] The method as set forth in claim 13, wherein the step of registering the IP address of the second video terminal with the first video terminal includes receiving and registering IP address information of a counterpart over the PSTN.

[15] The method as set forth in claim 13, wherein the step of registering the IP address of the second video terminal with the first video terminal includes, when the IP address information of the second video terminal is already known, registering the IP address information of the second video terminal using a GUI of the first video terminal.

[16] The method as set forth in claim 13, wherein the update data comprises a flag value indicative of whether the IP address of the first gateway has been changed, an ID (a central office line telephone number) of the first gateway, the changed IP address information of the first gateway, and a flag value indicative of whether the changed IP address of the first gateway has already been registered.

[17] A method of providing free video communication service between systems based on dynamic IP addresses, the method comprising the steps of a first gateway checking a state of connection with a gateway group that has been previously registered, in a booting process after power-on; when there is no response from a second gateway, transmitting a DTMF signal, requesting changed IP address information, to the second gateway over a PSTN; checking IP address information of the second gateway, which is currently assigned; the second gateway transmitting its current IP address to the first gateway as a DTMF signal; the first gateway changing and storing changed IP address information of the second gateway, which has been transmitted from the second gateway, in an existing stored data region; the first gateway transmitting address information, including its own IP, to the second gateway over an Internet using the stored IP address information of the second gateway; and the second video terminal registering the address information of the first gateway, including the IP, which has been received from the first gateway.

[18] The method as set forth in claim 17, wherein the step of requesting the DTMF signal, requesting the changed IP address information, to the second gateway over the PSTN is the step of an ARS of the first gateway transmitting a specific DTMF signal according to a guidance announcement output from the second gateway and requesting the current IP information of the second gateway.

[19] A method of providing free video communication service between systems based on dynamic IP addresses, the method comprising the step of a first video terminal transmitting a free communication service request signal to a second video terminal using previously registered IP address information; the second video terminal, which has received the free communication service request signal, generating a request event so that a user can be made aware of reception of the request signal; and the second video terminal receiving approval of video communication service from the user, connecting to the first video terminal over an Internet and providing the video communication service to the first video terminal.