JP3139070B2 - Communication terminal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device connected to an ISDN, and more particularly, to an intercommunication system through a complex communication network in which an ISDN and various existing communication networks are interconnected. The present invention relates to a communication terminal device having a function of re-calling a called terminal when a communication failure occurs.

[0002]

2. Description of the Related Art Communication networks to which communication terminals such as facsimile machines are connected have been mainly telephone networks and packet-switched data networks (hereinafter abbreviated as PSPDN). The integrated service digital network (hereinafter, abbreviated as ISDN) has been used. ISDN refers to the unification of information of various communication devices such as telephones, facsimile machines, and telexes connected to a home line termination unit (DSU) via a bus in a digital format, and communication services for these communication devices with the same number. It is a unified communication network.

In each of such communication networks, when a communication failure occurs, such as when the line between the calling terminal and the called terminal is not connected, or when the line is disconnected during communication, the situation according to the situation at that time is determined. The disconnection information is returned to the calling terminal. Each terminal device has a recall management table that uniquely defines the relationship between the disconnection information and the recall condition.
When the disconnection information is received, the re-calling management table is referred to based on the disconnection information, and the called terminal is called again under the re-calling condition according to the disconnection information.

[0004] Since the contents of the disconnection information differ for each communication network, the recall management table provided in each terminal device also differs depending on the communication network to be connected.
Is connected to the telephone network, and the terminal connected to the telephone network is the recalled call management table b.
The terminal device connected to N has one kind of re-call management table according to the communication network to be connected, such as the re-call management table c.

[0005]

In the early stage of the introduction of ISDN, interconnection between ISDN and other existing networks is an important issue. In particular, interconnection with the widely spread telephone network and PSPDN is important.

FIG. 2 shows a so-called case A defined by CCITT for the interconnection between ISDN and PSPDN.
FIG. 3 is a diagram showing the configuration of FIG. Case A is a type of service form for the PSPDN connected to the ISDN.

In case A, as shown in FIG.
N does not have a packet switching function, and the ISDN functions only as a physical subscriber line between the packet terminal 20 connected thereto and the packet switch in the PSPDN.

In this system, the ISDN packet terminal 2
When 0 requests packet mode communication through the D channel, the ISDN switch sets a digital path of 64 kbps unrestricted to an access unit (AU) for interconnecting ISDN and PSPDN and a packet terminal. Set between 20.

As a result, a subscriber line is completed between the ISDN packet terminal 20 and the PSPDN. Thereafter, the call control from the packet terminal 20 is replaced by the call control from the terminal directly accommodated in the PSPDN. Proceed exactly as described.

However, in the configuration of case A described above,
Since the target communication network is ISDN until the packet terminal 20 is connected to the AU, the network control is performed according to the call control procedure of the ISDN. However, when a line is set up between the packet terminal 20 and the AU, the target communication network becomes Since the call is switched to PSPDN, the subsequent call control is performed according to Recommendation X.31. This is performed according to 25 call control procedures.

Therefore, when a communication failure occurs in the ISDN procedure until the packet terminal is connected to the AU, the disconnection information defined by the call control procedure is returned, and the recommendation X.3 is provided. When a communication failure occurs in the 25th procedure, the disconnection information defined by the call control procedure is returned. Therefore, in the former case, the recalling management table c is referred to, and in the latter case, the recalling management table a is referred to. Need to refer.

However, the terminal 20 has a recall management table.
Since the only disconnection information is provided, the latter disconnection information cannot be sufficiently dealt with. As described above, in the related art, each communication terminal has only one type of re-calling management table, so that if the returned disconnection information differs for each communication network, re-calling control will not be performed properly. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to reliably re-call a called terminal in response to disconnection information returned when a communication failure occurs regardless of the type of the target communication network. It is to provide a terminal device.

[0014]

In order to achieve the above object, according to the present invention, a terminal on a complex communication network is connected via a complex communication network in which an ISDN and an existing communication network are mutually connected. In a communication terminal device that performs mutual communication with the device, a call control procedure according to a call condition and a calling means for calling a destination terminal under the communication condition, and a switch of a target communication network is detected to execute the call control procedure. A call control procedure changing means for changing; a disconnection information detecting means for detecting returned disconnection information; a recalling call management table storing means in which a plurality of recalling call management tables indicating a relationship between the disconnection information and the recalling condition are registered; A re-call management table selecting means for selecting a re-call management table according to the call control procedure from the re-call management table storage means, and a re-call from the selected re-call management table based on the returned disconnection information. And recalling condition selection means for selecting conditions to and a recalling means for recalling the destination terminal in the call control procedure and the communication conditions corresponding to the selected recalling condition.

[0015]

According to the above arrangement, the recall management table selecting means selects the recall management table according to the calling conditions. If a communication failure occurs during the calling operation and the disconnection information is returned, the re-calling condition selection means selects a re-calling condition according to the returned disconnection information from the re-calling management table. Therefore, the selected recall condition reliably corresponds to the disconnection information, and an appropriate recall can be performed.

[0016]

FIG. 1 is a functional block diagram of the present invention.

In FIG. 1, when a calling condition such as a subscriber number of a called terminal or a communication condition is input, a calling means 11 determines a call control procedure at the time of calling based on the calling condition.
The called terminal is called based on the call control procedure. The call control procedure changing means 14 changes the call control procedure of the calling means 11 by detecting the switching of the target communication network during the calling operation. In the re-call management table storage means 15, a plurality of re-call management tables are registered.

FIG. 3 is a diagram showing one embodiment of the structure of the re-call management table. Each recall management table is composed of disconnection information and recall parameters. The disconnection information includes a CPS value returned from the communication network when a communication failure occurs,
It is a value corresponding to the cause code or the reason display value, etc.
The recall parameter is an identifier for specifying a recall condition such as a call control procedure and a communication condition at the time of a recall.

The recall management table selecting means 13 selects a recall management table according to the call control procedure of the calling means 11 from the recall management table storage means 15. The disconnection information detecting means 16 detects disconnection information returned from the communication network when a communication failure occurs.

The recalling condition selection means 12 selects a recalling parameter from the selected recalling management table based on the returned disconnection information. For example, the content of the selected recall management table is as shown in FIG.
If the disconnection information is "0", "a1" is selected as a recall parameter.

The re-calling means 10 comprises a re-calling condition selecting means 1
Based on the re-calling parameters selected in step 2, re-calling conditions such as a call control procedure and communication conditions for re-calling are determined, and the called terminal is re-called under the re-calling conditions.

Hereinafter, the operation when the communication terminal device having the above configuration is applied to the case A described with reference to FIG. 2 will be described with reference to the flowchart of FIG. 6 and the sequence diagrams of FIGS. FIG. 7 is a sequence diagram when a communication failure does not occur, and FIG. 8 is a sequence diagram when a communication failure occurs.

When the operator performs a calling operation, in step S101, the calling means 11 determines a call control procedure at the time of calling based on the calling conditions. The type of the call control procedure is determined according to the call destination and communication conditions. For example, if the call request is to the terminal 21 shown in FIG. 2, the service according to the case A is selected. An ISDN call control procedure is selected to establish a route to the AU.

In step S102, for example, a recall management table c is selected from the recall management table storage 15 by the recall management table selector 13 as a recall management table responding to the call control procedure. In step S103, the calling means 11 makes a call to the AU according to the call control procedure.

At this time, as shown in FIGS. 7 and 8, between the calling terminal 20 and the ISDN, and between the ISDN and the PSDN
, An “call setting” signal, a “call setting accepting” signal, a “response” signal, and a “response confirmation” signal are transmitted and received.

In step S104, it is determined whether or not the call according to the call control procedure has been normally completed. As described above, the call control procedure has been normally completed, and a path is completed between the ISDN and the AU. Then, the target communication network of the calling terminal 20 is switched from ISDN to PSPDN, and the process proceeds to step S106.

On the other hand, if a communication failure occurs during the calling of the AU, the processing is performed from step S104 to step S105.
In step S105, the disconnection information sent from the ISDN is detected by the disconnection information detecting means 16. At this time, since the re-call management table c has been selected by the re-call management table selection means 13, the re-call condition selection means 12 selects a re-call parameter based on the re-call management table c and the disconnection information.

In step S106, the call control procedure changing means 14 detects the switching of the target communication network, and
1 is controlled by the ISDN
Recommendation X. Change to 25 call control procedures. When the call control procedure is changed, in step S107, the re-call management table selecting means 13 responds to the change from the re-call management table storage means 15 in place of the re-call management table c. Table a
Select In step S108, the recommendation X. A call is issued to the PSPDN according to the 25 call control procedures.

At this time, as shown in FIGS. 7 and 8, between the calling terminal 20 and the PSPDN, a restart request packet (SQ), a restart confirmation packet (SF), and a call request packet (CR) ) Is sent and received, and then P
Incoming call indication packet (CN) from SPDN to called terminal 21
Is sent.

In step S109, it is determined whether the calling of the called terminal 21 has been completed normally. As shown in FIG. 7, when the called response packet (CA) is returned from the called terminal 21 to the PSPDN, and the calling confirmation packet (CC) is returned from the PSPDN to the calling terminal 20, the call is normally transmitted. Is determined to have ended.

The calling terminal 20 sends a call confirmation packet (CC)
Is received and the calling of the PSPDN ends normally, in step S110, communication is performed between the calling terminal 20 and the called terminal 21 under the predetermined communication conditions.

On the other hand, if the call response packet (CA) is not returned in response to the call instruction packet (CN), it is determined in step S109 that a communication failure has occurred.
The process proceeds to step S115.

At this time, as shown in FIG.
N returns a disconnection instruction packet (CI) to calling terminal 20, and calling terminal 20 transmits a disconnection confirmation packet (CF) to PSPDN. Disconnect instruction packet (CI)
Is provided with cutting information, and this cutting information is detected by the cutting information detecting means 16. At this point, since the re-call management table a has been selected, step S1 is executed.
At 15, the re-calling condition selecting means 12 selects a re-calling parameter corresponding to the disconnection information from the re-calling management table a.

In step S111, a disconnection process is executed, and a call-out request packet (CQ) is transmitted from the calling terminal 20 to the PSPDN. The disconnection instruction packet (CI) is sent from the PSPDN to the called terminal 21, and the called terminal 21
Returns a disconnection confirmation packet (CF) from the PSPDN to the calling terminal 20.

In step S112, the calling terminal 20 and P
The line with SPDN is released, and the call control procedure of ISDN is selected again. In step S113, the re-call management table c is selected again from the re-call management table storage 15 by the re-call management table selecting means 13 as the re-call management table responding to the call control procedure.

Thereafter, in step S114, a disconnection process is performed, and the connection between the calling terminal 20 and the ISDN and the ISD
A “disconnect” signal, a “release” signal, and a “release confirmation” signal are exchanged between the N and the AU to end a series of communication operations.

As described with reference to FIG. 8, if a communication failure occurs and the recall parameter is selected by the recall condition selecting means 12, the recall means 10 makes a call operation based on the recall parameter. I do.

FIG. 4 is a block diagram of a facsimile apparatus according to one embodiment of the present invention.

In FIG. 1, a main controller 5 is connected to a bus 50.
1, G4 protocol control device 52, G3 / G2 protocol control device 53, line selection processing device 54, image information processing device 56, auxiliary storage control device 57, line control device (NC
U) 58, RAM 65, and ISDN protocol controller 55 are connected.

An operation panel 63 is connected to the main controller 51, and an auxiliary storage device 64 is connected to the auxiliary storage control device 57. The scanner 61 and the printer 62 are connected to the image information processing device 56 via interfaces 59 and 60, respectively. From the panel 63, communication conditions such as a communication mode such as G3 mode or G4 mode, an image quality mode such as standard or high definition, and a subscriber number of a called terminal are input.

The re-call management table is registered in the RAM 65 in advance. The contents of this recall management table can be added or modified by the operator operating the panel. The contents of the recall management table can be output from the printer 62 by operating the panel.

FIG. 5 is a schematic diagram showing a connection state between the ISDN to which the facsimile device 40 is connected and another communication network. In this embodiment, the telephone network and the PSP are connected to the ISDN.
The DN is connected between networks.

The operation when the calling condition is facsimile communication to the facsimile apparatus 41 in the G4 mode will be described below.

When the operator operates the panel 63 of the facsimile machine 40 to designate the G4 mode as the communication condition and input the subscriber number of the destination terminal to set the calling condition, the main control device 51 sets the calling condition. Is started, and the call control procedure of ISDN is selected as the call control procedure. A communication job is a program that manages a series of operations from the start to the end of communication.

When the communication job is started and communication control is started, the main controller 51 controls the line selection processor 54 to connect the G4 protocol controller 52 to the ISDN protocol controller 55. At the same time, main controller 51
Reads from the RAM 65 a re-call management table according to the ISDN call control procedure.

Thereafter, call control is started in accordance with the ISDN call control procedure. However, since the called terminal is connected to the telephone network, communication in the G4 mode is impossible, and the call is released and disconnection information is transmitted. Returned to calling terminal.

This disconnection information is input to the main control unit 51 via the ISDN protocol control unit 55, and the main control unit 51 selects a re-calling parameter in accordance with the disconnection information and the read-out re-calling management table.

When the communication job is restarted, main controller 51 refers to the recall parameter. The recall parameter can be appropriately set in advance, and if a parameter representing “communication in G3 mode” is registered as a parameter selected when communication in G4 mode is not possible, recall conditions can be set. Is facsimile communication in the G3 mode.

When the G3 mode is designated, main controller 5
1 sets a call control procedure of the telephone network as a call control procedure, and the line selection processing device 54 is a G3 / G2 protocol control device 5
3 and the ISDN protocol controller 55 are connected. The main controller 51 also recognizes that the network has been switched to the telephone network, and reads from the RAM 65 a recall management table according to the call control procedure of the telephone network.

When the re-call control is started in this way, the network can be connected to the telephone network this time, so that the communication according to the call control procedure of the telephone network is performed and the image read by the scanner 61 is read. The information and the image information stored in the auxiliary storage device 64 are sent to the facsimile device 41.

According to the present embodiment, since the re-call management table is selected according to the target communication network, it is possible to appropriately cope with the disconnection information for each communication network, and it is possible to reliably perform the re-call. .

Further, according to the present embodiment, since the contents of the recalling management table can be added and corrected, the recalling conditions can be easily changed, and the usability is improved.

[0053]

As is apparent from the above description, according to the present invention, a recall management table is selected according to a target communication network, and a recall condition is set based on the recall management table and the disconnection information. Since the decision is made, a reliable recall can be performed even in a complex communication network in which various types of communication networks are interconnected.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of the present invention.

FIG. 2 is a diagram showing a configuration of “Case A” defined by CCITT.

FIG. 3 is a diagram illustrating an example of a configuration of a re-call management table;

FIG. 4 is a block diagram of a facsimile apparatus according to one embodiment of the present invention.

FIG. 5 is a diagram showing a state in which a telephone network and a PSPDN are connected between ISDNs;

FIG. 6 is a flowchart showing the operation of FIG.

FIG. 7 is a sequence diagram showing the operation of FIG.

FIG. 8 is a sequence diagram showing the operation of FIG.

[Explanation of symbols]

10 ... Recalling means, 11 ... Calling means, 12 ... Recalling condition selecting means, 13 ... Recalling management table selecting means, 14 ...
Call control procedure changing means, 15: recall management table storage means, 16: disconnection information detecting means

Claims (2)

(57) [Claims] 1. A communication terminal device connected to an ISDN and mutually communicating with a terminal device on the complex communication network via a complex communication network in which the ISDN and an existing communication network are interconnected. Calling means for calling a called terminal under a call control procedure and communication conditions according to a call condition; and a call control procedure for detecting a change of a target communication network during a call operation and changing the call control procedure. Change means; disconnection information detecting means for detecting disconnection information returned when a communication failure occurs; recalling call management table storage means in which a plurality of recalling call management tables indicating a relationship between the disconnection information and recalling conditions are registered; A re-call management table selecting means for selecting a re-call management table corresponding to the call control procedure from the re-call management table storage means; and, based on the returned disconnection information, the selected re-call management table. A communication terminal device comprising: a re-calling condition selecting means for selecting a re-calling condition; and a re-calling means for re-calling a called terminal with a call control procedure and communication conditions according to the selected re-calling condition. . 2. The communication terminal device according to claim 1, further comprising means for correcting the contents of the re-call management table.