JP2653488B2 - Call transfer method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a call transfer method in a communication system including a communication network and a plurality of terminals.

[Conventional technology]

Conventionally, methods for transferring calls in a communication system include:
There are a method using a database provided in the communication system and a method for setting up a call from a call setting destination terminal to a call transfer destination terminal.

FIG. 3 shows the structure of a communication system that implements a method for transferring a call using a database provided in the communication system. In FIG. 3, it is assumed that the communication system has N terminals connected to a communication network. 301 is a communication network, a means 302 for communicating between terminals, and a means 303 for setting up a call between terminals.
Having. Reference numeral 307 denotes a terminal 1 having means 308 for setting up a call with the communication network and means 309 for performing communication via the communication network. The terminals 2 to N have the same means.
Reference numeral 304 denotes a database having a storage device 306 in which a call transfer destination is stored in advance for each terminal identifier for identifying a terminal by the communication network, and means 305 for searching the call transfer destination from the terminal identifier.

In the communication system of FIG. 3, a procedure when a call set up from terminal 1 to terminal 2 is transferred to terminal N will be described with reference to FIG. Here, a means for setting up a call with the communication network of the terminal N is denoted by 311 and a means for performing communication via the communication network is denoted by 312.

First, the call setting source terminal 1 sets up a call using the means 308 for setting up a call with the communication network (procedure). This call setting includes the terminal identifier (terminal 2) of the call setting destination. Means 303 for setting up a call with a terminal of the communication network 301 includes:
When the call setting from the terminal 1 is made, a transfer destination inquiry including the terminal identifier (terminal 2) included in the call setting is made by searching for the call setting destination from the terminal identifier in the database 304 (305).
Means (procedure), means 305 for searching for a call setting destination from the terminal identifier of the database 304, means for searching the storage device 306 and setting a call transfer destination (terminal N) with a terminal of the communication network 301. Returning to 303 (procedure), the means 303 for performing call setting with the terminal of the communication network 301 performs call setting for the means 311 for performing call setting with the communication network of the terminal N (procedure). Thereafter, means 30 for communicating via a communication network between terminal 1 and terminal N
9 and 312 perform communication via the means 302 for performing communication between the terminals of the communication network 301 (procedure) Next, a method for setting a call from a call setting destination terminal to a call transfer destination terminal and transferring the call is described. FIG. 5 shows the configuration of the communication system to be implemented. Also in FIG. 5, the communication system has N
It is assumed that one terminal is connected. Reference numeral 501 denotes a communication network having means 502 for performing communication between terminals and means 503 for performing call setting with the terminals. A terminal 504 includes a unit 505 for setting up a call with a communication network and a unit 506 for performing communication via the communication network. 507, a terminal 2; two means 508, 513 for setting up a call with the communication network; two means 509, 512 for performing communication via the communication network; and means 5 for performing communication within the terminal.
11 and means 514 for requesting a call setup with a predetermined call transfer destination as a call setup destination when a call setup is made from a communication network. The terminals 3 to N have the same means as the terminals 1 and 2.

In the communication system of FIG. 5, a procedure when a call set up from terminal 1 to terminal 2 is transferred to terminal N-1 will be described with reference to FIG. Here, the terminal N-1 has the same means as the terminal 1. A unit for setting up a call with the communication network of the terminal N-1 is denoted by 516, and a unit for performing communication via the communication network is denoted by 517.

First, the terminal 1 as a call setting source sets up a call using the means 505 for setting up a call with a communication network (procedure). This call setting includes the terminal identifier (terminal 2) of the call setting destination. Means 503 for setting up a call with a terminal of the communication network 501 includes:
Call setting is performed by means 508 for performing call setting with the communication network of the terminal 2 (procedure), and when a call is set from the communication network of the terminal 2, a call is set to a predetermined call transfer destination as a call setting destination. The means 514 for requesting the setting requests the call setting to the terminal N-1, and the means 51 for making the call setting with the terminal of the communication network of the terminal 2.
3 performs call setup (procedure). This call setting includes the terminal identifier of the call setting destination (terminal N-1). Communication network 50
The means 503 for setting up a call with one terminal sets up the means 516 for setting up a call with the communication network of the terminal N-1 (procedure). After this, the means 517 for communicating via the communication network of the terminal N-1 and the means 512 for communicating via the communication network of the terminal 2 communicate via the means 502 for communicating between terminals of the communication network. The means 509 for performing (procedure) and communicating via the communication network of the terminal 2 communicates with the means 512 for performing communication via the communication network using the means 511 for performing communication within the terminal, and the communication of the terminal 1 Means 506 for performing communication via the network and means 509 for performing communication via the communication network of the terminal 2 perform communication via means 502 for performing communication between terminals of the communication network (procedure).

[Problems to be solved by the invention]

In the above prior art, a method for transferring a call by a database provided in a communication system includes a storage device in which a call transfer destination is recorded in advance for each terminal identifier by which the communication network identifies a terminal, and a call transfer destination based on the terminal identifier. There is the disadvantage that a database having a means for searching must be provided. Also, a method for setting up a call from a call setting destination terminal to a call transfer destination terminal and transferring the call includes two means for setting up a call with a communication network, and communication through the communication network. There is a need for a terminal having two means for performing communication, a means for performing communication within the terminal, and a means for requesting call setting with a predetermined call transfer destination as a call setting destination when a call is set from a communication network. There are drawbacks, as well as the need for two simultaneous communications between the network and the terminal to transfer one call.

SUMMARY OF THE INVENTION An object of the present invention is to provide a call transfer method that can solve the above-mentioned drawbacks of the related art and can save the cost required for constructing a communication system and the communication cost.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a terminal includes means for notifying a communication network of a call transfer destination, a communication network includes means for notifying a terminal of a call transfer destination, and a terminal for call setting is provided in the communication network. When the notification of the call transfer destination is made from the communication network, the communication network notifies the call transfer source terminal of the call transfer destination, and the call setup source terminal sets up the call to the call transfer destination terminal. is there.

(Operation)

When a call transfer destination is notified from the call setting destination terminal to the communication network at the time of call setting, the communication network notifies the call setting source terminal of the call transfer destination, and the call setting source terminal notifies the call setting destination terminal. Perform call setup. Accordingly, a disadvantage that the communication network must be provided with a storage device in which a call transfer destination is pre-recorded for each terminal identifier for identifying a terminal, and a database having means for searching for the call transfer destination from the terminal identifier, , Two means for performing communication via a communication network, means for performing communication within a terminal, and a predetermined call transfer destination when a call is set from the communication network. Disadvantage that a terminal having a means for requesting call setup with a call setup destination is required,
The disadvantage of requiring two simultaneous communications between the communication network and the terminal to transfer one call is eliminated.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, the notation used in this embodiment will be described. FIG. 7 shows the configuration of a communication system used for explaining the notation. Reference numeral 701 denotes a terminal A having means a and means b. 7
02 is a communication network B having means c and d. FIG. 8 shows a description method of a message transmitted and received by a terminal and each means of a communication network in the notation used in this embodiment.

In FIG. 8, reference numerals 801, 802, 803, and 804 denote a description method of a message transmitted and received by each means of the terminal. Of these, reference numeral 801 denotes message reception within the terminal, for example, when the means a of the communication system of FIG. 7 receives a message from the means b. 802 is a message transmission to the communication column, for example, the seventh
The case where the means a of the communication system shown in the figure transmits a message to the communication network B is shown. Reference numeral 803 denotes a message reception from the communication network, for example, when the means a of the communication system of FIG. 7 receives a message from the communication network B. Reference numeral 804 denotes a message transmission inside the terminal, for example, when the means a of the communication system of FIG. 7 transmits a message to the means b. On the other hand, 805, 806, 807, and 808 are methods for describing messages transmitted and received by each means of the communication network. Reference numeral 805 denotes a message reception from the terminal, for example, when the means c of the communication system shown in FIG. Reference numeral 806 denotes message transmission within the communication network, for example, when the means c of the communication system of FIG. 7 transmits a message to the means d. 807 is a message reception inside the communication network, for example, the seventh
The case where the means c of the illustrated communication system receives a message from the means d is shown. 808 is a message transmission to the terminal,
For example, a case where the means c of the communication system of FIG. 7 transmits a message to the terminal A is shown.

In the notation used in this embodiment, the notation of the procedure of the transmission / reception message of the terminal or each means of the communication network is shown in FIG. FIG. 9 is an example of a procedure of a message transmitted and received by the means a of the terminal A in the communication system shown in FIG. 7. The means a of the terminal A is in the initial state, and means inside the terminal A (for example, means b )), The message γ is transmitted to the communication network B, and when the message β is received from the communication network B, the message δ is transmitted to the means inside the terminal A.
To return to the state again.
Further, FIG. 9 shows that, in the state of FIG.
This also indicates that when a message other than the above is received, the state remains.

FIG. 1 is a configuration example of a communication system that implements the call transfer method of the present invention. In the communication system of FIG. 1, it is assumed that N terminals are connected to the communication network.

In FIG. 1, reference numeral 101 denotes a communication network 1, a means 102 for performing communication between terminals, a means 103 for performing call setting between terminals,
Means 104 is provided for notifying the call transfer destination. 105 is terminal 1,
It has means 106 for setting up a call with a communication network, means 107 for performing communication via the communication network, and means 108 for notifying a call transfer destination. The terminals 2 to N have the same means as the terminal 1. Each means of the communication network and the terminal can transmit and receive information, a finite state machine that changes the internal state by transmitting and receiving information and transmits information according to the internal state, for example, transmits and receives information by packets It can be realized by a computer device having a device for transmitting and receiving packets from the device based on a predetermined procedure.

FIG. 2 shows a communication network when a call transfer method of the present invention is implemented in the communication system shown in FIG.
It is an example of a message notification procedure between a call setting destination terminal and a call transfer destination terminal. Of the messages shown in FIG. 2, messages other than call transfer can use a message configuration conforming to CCITT Recommendation I.451 (ISDN user / network interface-layer 3 specification).

FIG. 10 shows a configuration example of the information elements of the call transfer message and the contents thereof. The call transfer message includes a protocol identifier, a call number, a message type, and a call transfer destination. FIG. 11 shows an example of the contents of the protocol identifier. Eleventh
The protocol identifier shown in the figure is composed of one octet of information and conforms to CCITT Recommendation I.451. FIG. 12 shows an example of the contents of the call number. The call number shown in FIG. 12 is composed of two octets of information, includes a flag and a call number value, and includes a CCIT
Complies with T Recommendation I.451. FIG. 13 shows an example of the contents of the message type. The message type shown in FIG. 13 is composed of one octet of information, and is composed of a bit pattern that is undefined and defined by the message type of CCITT Recommendation I.451. FIG. 14 shows an example of the contents of the call destination. The call transfer destination shown in FIG. 14 is composed of information of 15 octets, and the content of each octet is composed of information obtained by encoding the terminal identifier of the call transfer destination, for example, information obtained by encoding the telephone number based on JISC6220. Is done.

Next, an example of the means of the message transmitted and received by the communication network and each means of each terminal in FIG. 1 will be described.

FIG. 15 shows an example of the procedure of a message transmitted and received by the means for setting up a call with the communication network of the terminal. The means for performing call setting with the communication network of each terminal receives the call setting 1502 from the communication network in the initial state 1501, and the call transfer destination is registered in advance in the means for performing call setting with the communication network. If it is determined that the call is not to be transferred, a response 1503 is sent to the communication network.
, A response confirmation 1504 is received from the communication network, a communication start 1505 is transmitted inside the terminal, a communication end 1506 is received from the terminal inside, a release 1508 is transmitted to the communication network, and a release completion 1509 is transmitted from the communication network. Receiving and returning to the initial state again. Also, the initial state
In 1501, a call setting 1502 is received from a communication network, and a call transfer destination is registered in advance in a means for setting up a call with the communication network. If it is determined that the call is to be transferred, the call is transferred to the terminal.
Send 1510 and return to the initial state again. On the other hand, the means for setting up a call with the communication network of each terminal does not receive the call setting from the communication network in the initial state 1501, and if it is not determined to perform the call setting for the communication network, the initial state If it is determined that the call setting is to be performed on the communication network, a call setting 1511 is transmitted to the communication network, and the call setting is received 1512 from the communication network.
When a response 1513 is received from the communication network, a communication start 1514 is transmitted inside the terminal, and a communication end 1514 is transmitted from the terminal.
When receiving 15 and releasing 1517 from the communication network, it transmits release complete 1518 to the communication network and returns to the initial state again. Also,
If a call transfer 1519 is received from the communication network after receiving the call setting reception 1512 from the communication network, a release 1520 is received from the communication network, a release completion 1521 is transmitted to the communication network, and the call setting 1511 is again performed.
Send

FIG. 16 shows an example of a procedure of a message transmitted / received by a means for performing communication via a communication network of each terminal. Means for performing communication via the communication network of each terminal, when receiving a communication start 1602 from inside the terminal in the initial state 1601, the communication state 1603
When the disconnection 1604 is received from the communication network in the communication state 1603, the communication end 1606 is transmitted to the inside of the terminal, and the terminal returns to the initial state again. Further, in the communication state 1603, the disconnection is not received from the communication network, and if it is not determined that the communication has been terminated, the communication state 1603 remains.If it is determined that the communication has been terminated, a disconnection 1605 is transmitted to the communication network. The communication end 1606 is transmitted to the inside of the terminal, and the terminal returns to the initial state again.

FIG. 17 shows an example of the procedure of a message transmitted and received by the means for notifying the call transfer destination of each terminal. Upon receiving the transfer 1702 from inside the terminal in the initial state 1701, the means for notifying the call transfer destination of each terminal transmits a call transfer 1703 to the communication network and returns to the initial state again.

FIG. 18 shows a means for setting up a call with a terminal of a communication network,
An example of a procedure of a message transmitted / received inside the communication network and for each terminal is shown. The means for performing call setting with the terminal of the communication network, when receiving the call setting 1802 from the terminal in the initial state 1801, transmits a call setting acceptance 1803 to the terminal, and transmits the call setting 1804 to the inside of the communication network. When a response 1805 is received from inside the communication network, a response 1806 is transmitted to the terminal, a communication start 1807 is transmitted to the communication network, a communication end 1808 is received from the communication network, and a disconnection 1810 is received to the communication network. It transmits, receives release 1811 from inside the communication network, transmits release 1812 to the terminal, receives release completion 1813 from the terminal, transmits release completion 1814 to the inside of the communication network, and returns to the initial state again. If the release 1815 is received from the inside of the communication network after transmitting the call setting 1804 to the inside of the communication network, the release 1816 is transmitted to the terminal and the release is completed from the terminal.
18147 is received, and it returns to an initial state again. Also, initial state 1
In 801, when the call setting 1818 is received from inside the communication network, the call setting 1819 is transmitted to the terminal, and when the response 1820 is received from the terminal, the response 1821 is transmitted to the inside of the communication network, and the response confirmation 1822 is transmitted to the terminal. Send, send communication start 1823 inside the communication network, receive communication end 1824 from inside the communication network, send disconnect 1826 to the terminal, receive release 1827 from the terminal, send release 1828 to the communication inside, Upon receiving release completion 1829 from the inside of the communication network, it transmits release completion 1830 to the terminal, and returns to the initial state again. Also, when a call transfer 1831 is received from the terminal after transmitting the call setting 1819 to the terminal, a call transfer 1832 is transmitted to the inside of the communication network and returns to the initial state again.

FIG. 19 shows an example of a procedure of a message transmitted / received inside the communication network and for each terminal by means for performing communication between terminals on the communication network. The means for performing communication between terminals of the communication network enters a communication state 1903 upon receiving a communication start 1902 from inside the communication network in the initial state 1901, receives a disconnection 1904 from the communication network or a disconnection 1905 from inside the terminal, and End of communication to 1906
And returns to the initial state again.

FIG. 20 shows an example of a procedure of a message transmitted / received inside the communication network and for each terminal by the means for notifying the call transfer destination of the communication network. The means for notifying the call transfer destination of the communication network transmits the call transfer 2003 to the terminal when the call transfer 2002 is received from the inside of the communication network in the initial state 2001, and releases the call to the inside of the communication network 2004
And returns to the initial state again.

The above-mentioned FIG. 15, FIG. 16, FIG. 17, FIG. 18, FIG. 19, FIG.
By the message procedure shown in FIG. 20, the message notification procedure shown in FIG. 2 is realized as follows.

In FIG. 1, it is assumed that the call setting source terminal is 105 terminal 1, the call setting destination terminal is 109 terminal 2, and the call transfer destination terminal is 113 terminal N. Also, in order to distinguish messages transmitted / received by each means of each terminal for each terminal, for example, a response 1503 transmitted by the means 106 for setting up a call with the communication network of the terminal 1 is transmitted.
Is described as response 1-1503. In order to distinguish messages transmitted and received by each means of the communication network for each terminal, for example, a call setting reception 1803 transmitted to the terminal 2 by a means for performing call setting with a terminal of the communication network is a call setting reception 1803. −18
Write 03.

Now, it is assumed that the procedure of a message transmitted / received by each means of each terminal to / from the terminal and the communication network and the procedure of a message transmitted / received by each means of the communication network to the inside of the communication network and each terminal are all in an initial state. . First, the means 106 for setting up a call with the communication network of the terminal 1 does not receive the call setting from the communication network in the initial state 1-1501, and sets the terminal 2 to the communication network as the call setting destination terminal. If it is determined that the call setup is to be performed, the call setup is performed on the communication network 1-15-111 (call setup 20 in FIG.
1) Send. The means 103 for performing call setting with the terminal of the communication network receives the call setting 1-1802 (ie, the call setting 201) from the terminal 1 in the initial state 1-1801, and sends the call setting reception 1 to the terminal 1. -1803 (call setting reception 202 in FIG. 2) and call setting 1-1804 to the inside of the communication network. The means 106 for performing call setting with the communication network of the terminal 1 receives the call setting reception 1-1512 (that is, the call setting reception 202) from the communication network.

The means 103 for making a call setup with a terminal of the communication network, when receiving the call setup 2-1818, ie, 1-1804 from inside the communication network in the initial state 2-1801, makes a call setup 2-1819 to the terminal 2.
(Call setting 203 in FIG. 2). The means 110 for setting up a call with the communication network of the terminal 2 receives the call setting 2-1502 (that is, the call setting 203) from the communication network in the initial state 2-1501, and performs a call with the communication network. When the call transfer destination terminal N is registered in the setting unit 103 and it is determined that the call transfer is to be performed, a transfer 2-1510 is transmitted inside the terminal, and the process returns to the initial state. The means 121 for notifying the call transfer destination of the terminal 2 receives the transfer 2-1702, that is, the transfer 2-1510 from the inside of the terminal in the initial state 2-1701, and the call transfer 2-1703 to the communication network.
(Call transfer 204 in FIG. 2) and return to the initial state.

The means 103 for setting up a call with a terminal of the communication network receives the call transfer 3-1831 (that is, the call transfer 204) from the terminal 2,
A call transfer 2-1832 is transmitted to the inside of the communication network, and returns to the initial state. The means 104 for notifying the call transfer destination of the communication network receives the call transfer 1-2002, that is, the call transfer 2-1832 from the inside of the communication network in the initial state 1-2001.
(Call transfer 205 in FIG. 2) and release to inside communication network 1
Send -2004 and return to the initial state again. Means 103 for setting up a call with a terminal of the communication network is released from inside the communication network.
When receiving "-1805", i.e., release 1-2004, it transmits release 1-1816 (release 206 in FIG. 2) to the terminal 1. The means 106 for setting up a call with the communication network of the terminal 1 receives the call transfer 1-1519 (ie, call transfer 205) from the communication network, and releases the call 1-1520 (ie, release 206) from the communication network. It receives and transmits release completion 1-1521 (release completion 207 in FIG. 2) to the communication network. The means 103 for setting up a call with the terminal of the communication network receives the release completion 1-1817 (that is, release completion 207) from the terminal, and returns to the initial state again.

The means 106 for making a call setup with the communication network of the terminal 1 is a call setup 1-terminal with the terminal N as a call setup destination terminal for the communication network.
1511 (setting 208 in FIG. 2) is transmitted. The means 103 for performing call setting with the terminal of the communication network receives the call setting 1-1802 (that is, the call setting 208) from the terminal 1 in the initial state 1-1801, and sends the call setting reception 1 to the terminal 1. -1803 (call setting reception 209 in FIG. 2), and the call setting into the communication network 1-1.
Send 804. The means 106 for setting up a call with the communication network of the terminal 1 receives the call setting reception 1-1512 (that is, the call setting reception 209) from the communication network.

The means 103 for setting up a call with a terminal of the communication network, when receiving the call setting N-1818, ie, the call setting 1-1804 from within the communication network in the initial state N-1801, sends the call setting N-
1819 (setting 210 in FIG. 2) is transmitted. The means 114 for setting up a call with the communication network of the terminal N is called from the communication network in the initial state N-1501 by the call setting N-1502 (that is, the call setting 210).
When it is determined that the call transfer destination is not registered in the means 110 for setting up a call with the communication network and the transfer is not to be performed, a response N-1503 (FIG. 2) is sent to the communication network. Send response 211).

The means 103 for setting up a call with a terminal in the communication network receives the response N-1802 (ie, the response 211) from the terminal N, and transmits the response N-1821 to the inside of the communication network. Means 103 for setting up a call with a terminal of this communication network is a response 1 from inside the communication network.
-1805, that is, the response N-1821, and sends a response 1-18 to the terminal 1.
06 (response 212 in FIG. 2) and a communication start 1-1807 to the inside of the communication network. The means 106 for setting up a call with the communication network of the terminal 1 receives the response 1-1513 (that is, the response 212) from the communication network, and transmits a communication start 1-1514 to the inside of the terminal. Means 103 for setting up a call with a terminal of a communication network,
A response confirmation N-1822 (response confirmation 213 in FIG. 2) is transmitted to the terminal N, and a communication start N-1823 is transmitted inside the communication network. The means 114 for setting up a call with the communication network of the terminal N receives the response confirmation N-1501 (that is, the response confirmation 213) from the communication network and transmits a communication start N-1505 to the inside of the terminal.

The means 107 for communicating via the communication network of the terminal 1 enters the communication state 1-1603 when the communication start 1-1602, that is, the communication start 1-1514 is received from the inside of the terminal in the initial state 1-1601, and the communication is terminated. Communication with the communication network (communication 214 in FIG. 2) is performed until it is determined that the communication has been completed, and when it is determined that the communication has been completed, disconnection 1-1605 (disconnection 215 in FIG. 2) is transmitted to the communication network, and the terminal A communication end 1-1606 is transmitted to the inside, and the process returns to the initial state again. The means 106 for setting up a call with the communication network of the terminal 1 receives a communication end 1-1515, that is, a communication end 1-1606 from inside the terminal.

The means 102 for performing communication between the terminals of the communication network is in the initial state 1
In step 1901, communication starts from inside the communication network.
Upon receiving -1807, the communication state becomes 1-1903, communication 214 is performed with terminal 1, and disconnection 1-1904 from terminal 1 (that is, disconnection 2
When receiving (15), the communication end 1-1906 is transmitted to the inside of the communication network, and the state returns to the initial state again. Means 103 for setting up a call with a terminal of the communication network includes communication termination 1-1808 from inside the communication network.
That is, when the communication end 1-1906 is received, a disconnection 1-1810 is transmitted inside the communication network.

Means 102 for performing communication between terminals of the communication network is in the initial state N
-1901, communication start from inside the communication network N-1902, that is, N
Upon receiving -1823, the communication state becomes N-1903, and communication 214 is performed with the terminal N. When disconnection N-1905, that is, disconnection 1-1810 is received from the inside of the communication network, communication is terminated to the inside of the communication network N-1906.
And returns to the initial state again. Means 103 for setting up a call with a terminal of the communication network includes communication termination N-1 from inside the communication network.
824, that is, when the communication end N-1906 is received, a disconnection N-1826 (disconnection 216 in FIG. 2) is transmitted to the terminal N.

The means 115 for performing communication via the communication network of the terminal N becomes the communication state N-1603 when the communication start N-1602, ie, the communication start N-1505, is received from the inside of the terminal in the initial state N-1601. 214 and disconnect from the communication network N-1604
Upon receiving (disconnection 216), a communication end N-1606 is transmitted to the inside of the terminal, and the terminal returns to the initial state. Upon receiving the communication end N-1506 from the inside of the terminal, ie, the communication end N-1606, the means 114 for setting up a call with the communication network of the terminal N is released to the communication network N-1508 (release 217 in FIG. 2). Send Upon receiving the release N-1827 (that is, release 217) from the terminal N, the means 103 for setting up a call with the terminal of the communication network transmits release N-1828 into the communication network.

The means 103 for setting up a call with a terminal on the communication network transmits a release 1-1812 (release 218 in FIG. 2) to the terminal 1 upon receiving the release 1-1811, that is, release N-1828, from inside the communication network. I do. Means 106 for setting up a call with the communication network of terminal 1
Receives the release 1-1517 (ie, release 218) from the communication network, and releases it to the communication network 1-11518 (release completion in FIG. 2).
219) and return to the initial state again. The means 103 for setting up a call with a terminal on the communication network is a
Upon receiving -1813 (that is, release completion 219), it transmits release completion 1-1814 to the inside of the communication network, and returns to the initial state again.
Upon receiving the release completion N-1829 or release completion 1-1814 from inside the communication network, the means 103 for setting up a call with the terminal of the communication network receives the release completion N-1830 (release completion 22 in FIG. 2).
0) and return to the initial state again. The means 114 for setting up a call with the communication network of the terminal N is a
Upon receiving -1509 (that is, release completion 220), it returns to the initial state again.

As is apparent from the above operation, the call transfer method of the present invention has a storage device in which a call transfer destination is pre-recorded for each terminal identifier for identifying a terminal by the communication network, and means for searching for the call transfer destination from the terminal identifier. Two means for setting up a call with a communication network without providing a database, two means for performing communication via a communication network, a means for performing communication within a terminal, and a method for setting a call from a communication network. In this case, a terminal having a means for requesting call setup with a predetermined call transfer destination as a call setup destination is not required, and two communications are simultaneously performed between the communication network and the terminal to transfer one call. And a communication system that realizes the call transfer method can be provided.

〔The invention's effect〕

As described above, if a communication system for performing call transfer according to the present invention is provided, there is no need to provide a database, so that there is an effect that costs required for communication system construction can be saved. Also, two means for setting up a call with the communication network, two means for performing communication via the communication network, a means for performing communication within the terminal, and a method for setting a call when the call setting is made from the communication network. Since there is no need to provide a terminal having a means for requesting call setting with the call transfer destination set as a call setting destination, there is an effect that costs required for constructing a communication system can be saved. In addition, since two communications are not required to transfer one call at the same time, the communication network can be operated efficiently and communication costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a communication system that implements the call transfer method of the present invention, and FIG. 2 is a communication network when the call transfer method of the present invention is implemented in the communication system of FIG.
FIG. 3 is a diagram illustrating an example of a message notification procedure between a call setting destination terminal and a call transfer destination terminal. FIG. 3 is a diagram illustrating a configuration example of a communication system illustrating a conventional method of transferring a call by a database provided in the communication system. FIG. 4 is a diagram showing a procedure when a call set from the terminal 1 is transferred to the terminal N in the communication system of FIG. 3, and FIG. 5 is a diagram showing a call from a call setting destination terminal to a call transfer destination terminal. FIG. 6 is a diagram showing an example of the configuration of a communication system for explaining a conventional method of transferring a call by setting a call, and FIG.
FIG. 7 is a diagram showing a procedure when a call set from a terminal 1 is transferred to a terminal N-1 in the communication system shown in FIG. 7, and FIG. 7 shows a configuration example of a communication system used for explaining a notation of an embodiment of the present invention. FIG. 8 is a diagram showing a description method of a message transmitted / received by each unit of the terminal or the communication network. FIG. 9 is a diagram showing a notation of a procedure of a message transmitted / received by each unit of the terminal or the communication network. The figure shows a configuration example of the information elements of the call transfer message and its contents, FIG. 11 shows the contents of the protocol identifier of FIG. 10, and FIG. 12 shows the contents of the call number of FIG. FIG. 13, FIG. 13 is a diagram showing an example of the content of the message type in FIG. 10, FIG. 14 is a diagram showing an example of the content of the call transfer destination in FIG.
FIG. 15 is a diagram showing an example of the procedure of a message transmitted and received by the means for setting up a call with the communication network of each terminal in FIG. 1, and FIG. 16 is a diagram showing communication through the communication network of each terminal in FIG. FIG. 17 is a diagram showing an example of a procedure of a message transmitted and received by the means for performing, FIG. 17 is a diagram showing an example of a procedure of a message transmitted and received by the means for notifying the call transfer destination of each terminal of FIG. 1, and FIG. 18 is a diagram of FIG. FIG. 19 is a diagram showing an example of a procedure of a message transmitted and received by the means for setting up a call with a terminal of a communication network inside the communication network and for each terminal.
A diagram showing an example of a procedure of a message transmitted and received by the means for performing communication between terminals of the communication network in the communication network and for each terminal,
FIG. 20 is a diagram showing an example of the procedure of a message transmitted and received by the means for notifying the call transfer destination of the communication network of FIG. 1 inside the communication network and for each terminal. 101: communication network, 102: means for communication between terminals, 103
... means for setting up a call with the terminal, 104 ... means for notifying the call transfer destination, 105, 109, 113 ... terminals, 106, 110, 114 ...
... means for setting up a call with a communication network, 107, 111, 115 ...
Means for communicating via a communication network, means for notifying a call transfer destination;

Claims (1)

(57) [Claims] 1. A communication network and a plurality of terminals connected to the communication network, a procedure for setting up a call between the communication network and the terminal is predetermined, and the communication network and the terminal are respectively connected to the communication network and the terminal. In a communication system having means for setting up a call between terminals and means for communicating between terminals via a communication network, the terminal includes means for notifying the communication network of a call transfer destination, and the communication network notifies the terminal of the call transfer destination. Notification means, and when a call transfer destination is notified from the call setting destination terminal to the communication network, the communication network notifies the call setting source terminal of the call transfer destination, and the call setting source terminal Is a call transfer method, wherein the call setting is performed by using the call transfer destination as a call setting destination.