JPH09168065A - Speech system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the speech even in the case that a terminal equipment of an opposite party cannot be connected to a server. SOLUTION: The system is made up of a computer network, terminal equipments of the computer network are interconnected via a server S31, and data including at least voice data are transferred in the computer network. The server S31 is provided with a database DB31 in which call information for the connection to destinations is stored. When a caller terminal equipment T31 makes a call to the server, the server S31 of the computer network uses the database DB31 to retrieve a connection destination of an opposite terminal equipment. When the connection is unsuccessful, a public telephone line TEL31 is used for the speech. When an internet telephone terminal cannot connect to the server S31 because of problems of line setting and software setting of the terminal, since the connection is made by a conventional phone call, even when the opposite terminal equipment cannot connect to the server, the speech is made available.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call system suitable for use as an internet telephone that transmits and receives voice data using the internet, which is a worldwide computer network.

[0002]

2. Description of the Related Art The Internet is a computer network in which computer networks existing in companies, universities, and the like are connected via a wide area line, and is spread all over the world. Various services using the Internet, such as an e-mail service, a file transfer service, and an information search service, have been actively performed.

FIG. 12 shows an outline of the Internet. In FIG. 12, NET101 and NET10
2, NET 103, ... Are computer networks. Computer network NET101, NET
102, NET 103, ... Each of a plurality of terminals T,
It has T, T, ... The terminals T, T, T, ... Of the computer networks NET101, NET102, NET103, ... Are respectively LAN (Local Area Network).
Connected by As the form of LAN, Ethernet, token ring, or the like is used.

[0004] Each computer network NET10
1, NET102, NET103, ... Are connected to each other via routers R101, R102, R103 ,. The routers R101, R102, R103, ... Perform routing processing for delivering data on a computer network to other computer networks depending on the destination.

As described above, the computer network N
The ET101, NET102, NET103, ... Are connected via routers R101, R102, R103 ,. Such a computer network is called the Internet. By the Internet, computer networks NET1, NET2, N all over the world
Data can be transferred between ET3, ....

On the Internet, IP (Internet Protocol) is used as a protocol of the network layer. In IP, an IP address is assigned to each terminal, and the destination to which the data is transferred is identified by the IP address. The IP address is composed of four numbers that can be represented by 8 bits in binary number. For example, "43.3.25.24
6 ”.

[0007] With the spread of the Internet, a shortage of IP addresses is feared. Therefore, when the number of terminals registered on a certain network is large and the number of terminals actually connected is small, etc., in order to save IP addresses, a server that allocates an IP address on the network is provided. Only when the device is connected,
There is a case where a vacant IP address is assigned. By doing so, it is not necessary to prepare IP addresses for the number of terminals, and a limited number of IP addresses can be used effectively.

On the Internet, TCP (Transmission Control Protocol) is used as a transport layer protocol.
otocol) and UDP (User Datagram Protocol). TCP is a so-called connection type communication connection, and then performs communication, and has functions of packet order control, retransmission, flow control, and congestion control. U
DP is a connectionless protocol and is used in place of TCP when real-time processing is required. For example, in digital voice communication, even if a part of a packet is dropped, the packet is not requested to be retransmitted, and the voice is transmitted without interruption. In the case of such voice communication, UDP is used.

As described above, the Internet basically uses the TCP / IP protocol. That is, an IP address is assigned to a terminal of the computer network, and this IP address is used for identifying the terminal. Then, the packet is transferred by TCP or UDP.

[0010] However, personal computers are not always connected to a LAN and may not have an IP address. Therefore, when an individual participates in the Internet, a company called an Internet service provider is used. When an Internet service provider is used, a personal computer can be connected to a computer network using a telephone line, for example, PPP (Point to Point Protocol) or SLIP (Serial Line IP), and can participate in the Internet.

That is, FIG. 13 shows an example of the Internet service provider. The computer network NET151 of the Internet service provider is
It has a server S151 and a router R151. The server 151 uses the modems M151, M152, M153,
Is connected to the public telephone line network TEL 151 via.

The terminals T151, T152, T153,...
Is a terminal of a person who individually participates in the Internet.
The terminals T151, T152, T153,... Are connected to a public telephone network TEL151 via a modem (not shown). Personal terminals T151, T152, T153, ...
As the, a personal computer having a serial port can be used.

When participating in the Internet using an Internet service provider, it is usual that a contract is signed in advance between the user and the company of the Internet service provider. When a contract is signed between the user and the Internet service provider, the user is sent an account name and password.

Personal terminals T151, T152, T15
When participating in the Internet from 3, ..., the user dials the Internet service provider and calls the computer network NET151 of the Internet service provider. Upon receiving the call, the server S151 requests the input of the account name and the password, and authenticates whether or not the contract is concluded with the Internet service provider. When the entered account name and password are correct and it is authenticated that the contract is signed with the Internet service provider, the server S151 searches for a free IP address, and if there is a free IP address, , The terminals T151 and T1 using this IP address as a temporary IP address.
52, T153, ... This allows the terminal T
A temporary IP address is attached to 151, T152, T153, ..., It becomes possible to connect to the Internet.

In the above example, the telephone line is used for P
Although it is connected by PP, ISDN (Integrated Service D
igital Network) may be used. ISDN
In 64, one channel has two B channels of 64 kbps and one D channel of 16 kbps, which is a total of three channels. With ISDN, 64 kbps by streaming IP packets over the B channel
It can be used as a line.

[0016]

The development of an internet telephone for making a call with the other party using the internet is under way. For internet telephones that use the internet to make phone calls, charges caused by a contract with an internet service provider, telephone charges to the internet service provider, and ISDN
You will be able to make calls only with the usage fee, and you will be able to make long-distance and international calls at very low rates.

However, there is a case where the other party's terminal is not ready to be connected to the Internet even if a telephone capable of making a call using the Internet is used. In addition, the terminal of the Internet telephone may not be able to connect to the server of the provider due to problems such as line setting problems and terminal software setting problems. A telephone that uses only the Internet cannot be used at all unless the other party can connect to the server.

Therefore, an object of the present invention is to provide a call system for making a call using the Internet, even if the other party's terminal cannot connect to the server. Especially.

[0019]

According to the present invention, a computer network is formed, connections between terminals of the computer network are made via a server, and data including at least voice data is transferred by the computer network. The call system according to claim 1, wherein the server has a database in which call information for connecting to the other party is stored, and is included in the computer network from the first terminal included in the computer network. If there is a connection request to the second terminal which does not exist, the calling information of the second terminal is searched using the database, the second terminal is called using the searched calling information, and the second terminal is connected to the computer network network. Try to connect to the Internet, and if the connection is unsuccessful, use the public telephone line to connect. A call system, characterized in that to perform the.

When the terminal of the Internet telephone cannot connect to the server due to a problem of setting the line, a problem of setting the software of the terminal, or the like, a normal telephone is used for connection. Therefore, it is possible to make a call even when the other terminal cannot connect to the server.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is applied to an Internet telephone that communicates voice data using the Internet, and is particularly used when the Internet telephone is used in a PPP connection using a public telephone line network. It is suitable.

FIG. 1 shows an example of an internet telephone system to which the present invention is applied. In FIG. 1, a computer network NET1 is, for example, a computer network of an Internet service provider. The computer network NET1 is
It has a server S1 and a router R1.

The server S1 includes modems M1, M2, M3,
Are connected to the public telephone network TEL1 via. At present, it is possible to transmit data at 28.8 Kbps using a public telephone network TEL1 by a high-speed modem.

The computer network NET1 is connected to another computer network forming the Internet via the router R1. Router R1
Performs a routing process of delivering data on a computer network to another computer network depending on the destination.

The terminals T1, T2, T3, ... Are terminals of individuals who individually participate in the Internet. Terminal T
As 1, T2, T3, ..., a personal computer in which an Internet telephone program is installed can be used, or a dedicated Internet telephone can be used. As will be described later, the dedicated Internet telephone is a terminal dedicated to the Internet telephone that enables easy telephone communication using the Internet.

The server S1 has a database DB1. As shown in FIG. 2, the database DB1 includes:
"Terminal name", "terminal Japanese name", "notation name on the Internet", "connection type", "PPP telephone number",
"User name" is recorded. Database DB1
Is constructed, for example, using information obtained from the contents of a contract when a contract is concluded between the Internet service provider and the user. If the connection type is PPP, this database DB1 contains the PPP of the person who has contracted with the Internet service provider via PPP connection.
Phone number information is included.

In this example, the server S1 and the terminal T
, 1, T2, T3, ... Are connected by PPP through a public telephone line network, but may be connected by using a digital network such as ISDN.

Next, call control in the call system to which the present invention is applied will be described. For example, in FIG. 1, it is assumed that the terminal T1 calls the terminal T2 to make a call. On the Internet, the IP address is used to identify the other party. In this case, the other terminal T2
Since it is a terminal connected by PPP, it is not always connected to the computer network NET1. Therefore, it is not possible to call the other party's terminal T2 using the IP address. Therefore, the database DB1 is used.

That is, FIG. 3 is a flow chart showing the procedure at that time. First, the terminal T1 on the calling side dials the Internet service provider NET1 to call the Internet service provider NET1. When the server S1 of the Internet service provider NET1 receives the call, it requests the terminal T1 to input an account name and a password, and makes an authentication request as to whether or not a contract has been concluded with the Internet service provider. The user of the terminal T1 on the calling side inputs the account name and password in response to the authentication request.
When the entered account name and password are correct and it is verified that the contract is signed with the Internet service provider, the server S1 assigns a temporary IP address to the terminal T1. Thereby, the terminal T1
A PPP connection with is started (step ST1).

Next, the terminal T1 designates the address of the other party (for example, the terminal T2) with which the call is to be made (step ST2).

When the destination address is designated, the server S1 searches the information of the terminal T2 using the database DB1. From the information in the database DB1, the terminal T2
The telephone number for the PPP connection is known (step ST).
3).

The server S1 determines the IP address for designating the partner terminal T2 in the server, prepares for the PPP connection, and notifies the calling terminal T1 of the IP address of this partner terminal (step ST4). ).

The server S1 is a database DB.
Dial the telephone number of the terminal T2 retrieved from 1 and call the terminal T2. When the connection of the telephone line with the partner terminal T2 is confirmed, the server S1 performs authentication and assigns an IP address to the partner terminal (step ST5).

As a result, the PPP connection is started (step ST6). Then, voice data is transmitted and received between the terminals T1 and T2, and a call is made (step ST
7). The audio data is compressed and transmitted. When transmitting and receiving voice data, UDP is used as a transport layer protocol.

When the call ends, the terminal T1 and the server S1
PPP connection and telephone line connection with terminal T2 and server S
All connections such as PPP connection and telephone line connection with No. 1 are terminated (step ST8).

In the above example, the IP address of the terminal T2 is determined before the call of the terminal T2 is completed. However, the IP address of the terminal T2 is determined after the call of the terminal T2 is completed. You may do it. At this time, the determined IP address may be notified to the calling terminal T1 as required. When the server determines the IP address of the other terminal, the calling
By informing the P address, the caller can prepare for communication with the other terminal in advance, so that it is possible to smoothly start the call between the terminals.

As described above, the database DB1 having the information of the telephone number for PPP connection is provided, and when the other party of the call is the terminal of PPP connection (for example, T2), the telephone number information of this database DB1 is used as the basis. , The other terminal is called. Then, the terminal T2 on the other side is PPP
Is connected to the server S1. As a result, even when the other party of the call is a PPP-connected terminal, the other party can be called to make a call.

In the above-mentioned example, the case where the terminals in the same computer network talk with each other has been described, but the terminals in other computer networks can also talk with each other. FIG. 4 shows an example in which a call is made between terminals between different computer networks.

In FIG. 4, the computer network NET11 is, for example, a computer network of an internet service provider. The computer network NET11 includes a server S11 and a router R.
11 are provided. The server S11 is a modem M11,
Public telephone line network TEL1 via M12, M13, ...
1 connected. Server S11 is database D
It has B11. The database DB11 stores information including telephone numbers of terminals connected to the computer network NET11 by PPP. The computer network NET11 is connected to another computer network constituting the Internet via a router R11. The router R11 performs a routing process for delivering data on the network to the network according to its destination. Terminal T
11, T12, T13, ... Are terminals of individuals who individually participate in the Internet.

The computer network NET21 is
For example, a computer network of another Internet service provider. The computer network NET21 has a server S21 and a router R21. The server S21 uses the modems M21, M22, M
, 23 are connected to the public telephone line network TEL21. The server S21 has a database DB21. The database DB21 stores information including telephone numbers of terminals connected to the computer network NET21 by PPP. The computer network NET21 is connected to another computer network forming the Internet via the router R21. The router R21 performs a routing process for delivering data on the network to the network according to its destination. Terminals T21, T2
2, T23, ..., For example, are terminals of persons who individually participate in the Internet.

For example, the computer network NET
From the terminal T11 of 11 to the computer network NE
It is assumed that a call is made to the terminal T21 of T21. In this case, FIG.
The processing shown in FIG.

First, the calling terminal T11 dials the network NET11 of the Internet service provider, and the server S11 of the computer network NET11 is called.

When the server S11 receives the call, the server S11 requests the input of the account name and the password, and requests the authentication as to whether or not the contract is concluded with the Internet service provider.

The user of the terminal T11 on the calling side inputs the account name and password in response to the authentication request. If it is verified that the entered account name and password are correct and that a contract has been made with the Internet service provider, server S11 assigns a temporary IP address to terminal T11. This allows
The PPP connection of the terminal T11 is started.

Next, the terminal T11 sends a call request to the server S11, and the server S11 returns a call response to the terminal T11. When the call response is returned, the address (for example, terminal T21) of the other party with whom the call is desired is specified.

When the address of the call destination is designated, the server S11 including the terminal on the calling side is connected to the computer network including the other side (for example, the computer network NE).
For example, a call request to the terminal T21 is sent to the server S21 in T21). Upon receiving the call request to the terminal T21, the server S21 returns a call response to the server S11. Server S11 of network NET11 including terminal on the calling side
Receives the call response, sends the address of the called party, and sends the information of the calling side.

Computer network N including the other party
The server S21 of the ET 21 uses the database DB21 to search for information on the terminal T21. Database DB
From the information of 21, the telephone number for the PPP connection of the terminal T21 can be known. The server S21 of the computer network NET21 dials the telephone number of the terminal T21 retrieved from the database DB21 and calls the terminal T21.

Upon receiving the call from the server S21, the terminal T21 on the partner side returns a call response to the server S21. Upon receiving the call response, the server S21 receives the call response
When making a connection request and receiving the PPP connection request, the terminal T21 notifies that a PPP connection is to be made.

Then, the server S21 requests the input of the account name and the password and performs the authentication. The user on the other side inputs an account name and a password according to the authentication. When it is confirmed that the entered account name and password are correct and a contract has been made with the Internet service provider, an IP address is assigned to the terminal T21. Thereby, P of terminal T21
The PP connection is started.

When the PPP connection is started, the server S21
Sends a call request to the terminal T21, and the terminal T21 returns a call response to the server S21. Then, the call connection completion is sent from the server S21 of the computer network NET21 to the server S11 of the computer network NET11, and the call completion is sent from the server S11 to the terminal T11. Then, the terminals T11 and T21
The voice data is transmitted and received between and to make a call.

When the call is completed, for example, the calling terminal T1
When a disconnection request is issued from No. 1, the disconnection request is sent to the terminal T21 on the other side. Upon receiving the disconnection request, the terminal T21 returns a disconnection response to the terminal T11 and disconnects all connections.

In this internet telephone system, a dedicated internet telephone can be used as a terminal.

FIG. 6 shows an example of the Internet telephone. In FIG. 6, reference numeral 1 is a telephone body.
A display operation unit 2 is provided on the upper surface of the telephone body 1.
The display operation unit 2 includes a display panel 3 as shown in FIG.
The touch panel 4 is laminated on the top. An icon indicating a numeric key or operation key is displayed on the display operation unit 2, and when the touch panel 4 on this icon is pressed,
You can make the necessary input. In addition to the icons indicating keys and the like, the display / operation unit 2 also displays help for operating guidance and setting status. Further, various information is displayed on the display operation unit 2. A handset 5 is connected to the telephone body 1. This telephone body 1 is connected to a public telephone line.

FIG. 8 shows the internal structure of the Internet telephone. In FIG. 8, reference numeral 11 is a CPU. The CPU 11 includes a ROM 12, EPROM 13, and R
AM14 is connected. Further, an input is given to the CPU 11 from the touch panel 4, and the output of the CPU 11 is displayed on the display panel 3.

The CPU 11 performs dial connection processing, IP data transfer processing, and audio signal compression / expansion processing. That is, when the address of the other party is input to the input from the touch panel 4, the CP
The U 11 controls the NCU 14 to dial the telephone number of the computer net of the Internet service provider and perform the telephone connection processing. Then, when the telephone connection is completed, connection processing by PPP is performed. In addition, a PPP connection may be requested upon receiving an incoming call from the computer network of the Internet service provider. Also in this case, the CPU 11 performs a telephone connection process,
When the telephone connection is completed, PPP connection processing is performed.
During a call, compress / transmit audio signals
The decompression process is performed and the IP communication process is performed.

The audio signal from the microphone of the handset 5 is digitized by the A / D and D / A converter 18. This digital audio signal is C
It is sent to the PU 11 and subjected to compression processing. Then, the compressed audio signal is transmitted via the modem 15 to the NCU (Node
Control Unit) 16.

The compressed audio signal sent via the telephone line is sent to the CPU via the NCU 16 and the modem 15.
11 is sent. The CPU 11 performs audio signal expansion processing. The expanded digital audio signal is sent to the A / D and D / A converter 18 and converted into an analog signal. Then, it is supplied to the speaker of the handset 5.

The Internet telephone can be used as an ordinary telephone. When functioning as an ordinary telephone, the handset 5 and the NCU 14 are connected to each other via the speech net 17, and a telephone call is performed using an analog voice signal via a telephone line.

Usually, in order to use the Internet telephone by the PPP connection, it is necessary to prepare a personal computer, connect a microphone and a speaker to the personal computer, and install software for the Internet connection. However, preparing a personal computer so that it can be connected to the Internet is not easy for a user who is not familiar with the computer. In addition, if a computer is used for PPP connection and an internet telephone is used, the operability is poor and the cost increases.

It is not necessary to incorporate software for connecting to the Internet in the above-mentioned Internet telephone,
You can easily connect to the Internet and perform voice communication. Also, as with ordinary telephones, the handset 5
Is provided and can be operated in the same way as a normal telephone.
Therefore, even a user unfamiliar with the computer can easily use the Internet telephone. Particularly, in the above-described Internet telephone, the display operation unit 2 having the structure in which the touch panel 4 is laminated on the display panel 3 is provided, and thus the operability is good.

By the way, there is a case where the other party's terminal is not ready to be connected to the Internet even if a telephone capable of making a call using the Internet is used. In addition, the terminal of the Internet telephone may not be able to connect to the server of the provider by PPP due to a problem of line setting, a problem of software of the terminal, or the like.

Therefore, as shown in FIG. 9, a public line connection adapter ADP31 is provided on the server side, and a line exchange PBX31 is provided. Circuit switch PBX31
Depending on whether the line connection or the PPP connection is successful, the mode is switched to the modem M31, M32, M33, ... Side and the public line connection adapter ADP31 side. That is,
First, the line switch PBX31 is connected to the modems M31, M32,
When set to M33, ..., calls the terminal on the other side, attempts connection, and when this is unsuccessful, a public telephone call is switched using the public line connection adapter ADP31.

For example, in FIG. 9, it is assumed that there is a connection request to the terminal T31. As the terminal 31, for example, a telephone dedicated to the Internet as shown in FIG. 8 is used.

In this case, as described above, the server S31
Searches for information on the terminal T31 using the database DB31 and tries to connect to the terminal T31. Then, as described above, the authentication is performed, and if the authentication is established, the IP address is allocated and the connection is established by PPP. Terminal T31 is P
When the PP connection is established, voice data is transmitted and received.

The signal flow at this time is, for example, the server S31, the modem M31, the line exchange PBX31, the telephone line network TEL31, and the terminal T31. And terminal T3
1, data is exchanged via the modem 15,
The / D and D / A converters 12 convert analog voice signals and digital voice data.

Here, line connection with the terminal T31 and PPP
Suppose the connection was unsuccessful. In this case, a public telephone connection is made using the public line connection adapter ADP31. If the connection of the modem is successful, a response signal is returned from the modem. Therefore, by detecting the response signal from the modem, it is possible to know whether the line connection with the terminal T31 was successful. Further, it can be known whether the PPP connection with the terminal T31 has succeeded or not depending on whether the authentication is established. In addition, even if a busy signal is returned or if you try to connect for more than a predetermined time and there is no response and you can not connect to the line, it may be possible to connect if you try to connect with a normal phone, so in this case Also, an ordinary telephone connection is tried by using the public line connection adapter ADP31. Furthermore, even if the connection by PPP is successful,
If the call application does not work well, use the public line connection adapter ADP31 to
A normal telephone connection is attempted.

In FIG. 10, when the PPP connection with the terminal T31 is unsuccessful, the server S31 allocates the IP address to be assigned to the terminal T31 to the public line connection adapter ADP31, and the server S3.
1 and the public line connection adapter ADP31 are connected by a LAN. At the same time, the line exchange PBX31 is set on the public line connection adapter ADP31 side. Then, the voice data encoding / decoding is performed by the public line adapter A.
The CPU 21 of the DP 31 performs the conversion with the digital voice data, and the conversion of the public line connection adapter ADP31 A /
This is performed by the D and D / A converter 22. A telephone call is made between the public line connection adapter ADP31 and the terminal T31 by an ordinary telephone. In addition, since a normal telephone call is made, at this time, the terminal 31 functions as a simple telephone rather than a terminal.

The signal flow at this time is, as shown in FIG. 10, the server S31 and the public line connection adapter ADP3.
1, a line exchange PBX31, a telephone line network TEL31, and a terminal T31. Data is exchanged between the server S31 and the public line connection adapter ADP31, and the digital voice data is processed by the public line connection adapter ADP31. Public line connection adapter ADP3
1, analog voice signals flow through the line exchange PBX31, the telephone line network TEL31, and the terminal T31. At the terminal T31, a speech is made by the speech net 17.

FIG. 11 is a flowchart showing an example of the above operation. In FIG. 11, a call is made from the server to the terminal (step ST11), and it is determined whether the line connection is successful (step ST12). If the line connection is successful, PPP connection is tried (step ST1).
3). It is determined whether or not the PPP connection is successful (step ST14), and if the PPP connection is successful, the call application is run and the call is made (step ST15). It is determined whether or not the call connection is successful (step ST16), and if the call connection is successful, the call is started (step ST17).

When it is determined in step ST12 that the line connection is not successful, the line is disconnected (step ST1
8) The line route is switched to make a call as a normal voice telephone (step ST19). It is determined whether or not the line connection is successful (step ST20). If the line connection is successful, the process goes to step ST17 to start the call. Here, if the line connection is unsuccessful, the calling side is notified of the connection failure (step ST21), and the process ends.

If it is determined in step ST14 that the PPP connection is unsuccessful, or if it is determined in step ST16 that the call connection is unsuccessful, the line route is switched and the connection is established as a normal voice call. (Step T
22). It is determined whether the connection is successful (step ST23), and if the line connection is successful, step ST17.
And the call is started. If the line connection is unsuccessful, the caller is notified of the connection failure (step ST2).
4) and the process ends.

[0072]

According to the present invention, when the terminal of the Internet telephone cannot connect to the server due to the problem of the setting of the line, the problem of the software of the terminal, etc., the ordinary telephone is connected. Therefore, it is possible to make a call even when the other terminal cannot connect to the server.

[Brief description of the drawings]

FIG. 1 is a block diagram used to describe an example of an Internet telephone system to which the present invention can be applied.

FIG. 2 is a schematic diagram used for explaining an example of an internet telephone system to which the present invention can be applied.

FIG. 3 is a flowchart used to describe an example of an internet telephone system to which the present invention can be applied.

FIG. 4 is a block diagram used for explaining another example of the Internet telephone system to which the present invention can be applied.

FIG. 5 is a flowchart used for explaining another example of the Internet telephone system to which the present invention can be applied.

FIG. 6 is a perspective view of an example of a telephone used in an internet telephone system to which the present invention can be applied.

FIG. 7 is a cross-sectional view used to explain an example of a telephone used in an internet telephone system to which the present invention can be applied.

FIG. 8 is a block diagram of an example of a telephone used in an internet telephone system to which the present invention can be applied.

FIG. 9 is a block diagram used for explaining an example of an Internet telephone system to which the present invention is applied.

FIG. 10 is a block diagram used for explaining an example of an Internet telephone system to which the present invention is applied.

FIG. 11 is a flowchart used to describe an example of an Internet telephone system to which the present invention is applied.

FIG. 12 is a block diagram used for explaining the Internet.

FIG. 13 is a block diagram used to describe a PPP connection.

[Explanation of symbols]

 S31 server ADP31 line adapter PBX31 line switch

Claims (6)

[Claims] 1. A computer network is formed,
A call system in which each terminal of the computer network is connected via a server, and data including at least voice data is transferred by the computer network, wherein the server connects to a destination. When a connection request is made from a first terminal included in the computer network to a second terminal not included in the computer network, the database is stored. Using the retrieved call information to call the second terminal, attempting to connect the second terminal to the computer network, and connecting the second terminal to the computer network. If the call is unsuccessful, the public telephone line is used to make the call. Call system that. 2. The call system according to claim 1, wherein whether or not the connection is unsuccessful is detected by a response signal from a modem. 3. The call system according to claim 1, wherein whether or not the connection is unsuccessful is detected based on whether or not the authentication is successful. 4. The call system according to claim 1, wherein whether or not the connection is unsuccessful is detected based on whether or not an application operates normally. 5. The call system according to claim 1, wherein whether or not the connection is unsuccessful is detected based on whether or not a busy signal is returned. 6. The call system according to claim 1, wherein whether or not the connection is unsuccessful is detected by whether or not there is a response within a predetermined time.