JPH05114948A - Automatic redialling system - Google Patents

Abstract

PURPOSE:To automatically set the setting of the redialling interval and the redialling frequency to an optimum value in accordance with the condition of an opponent equipment. CONSTITUTION:A control part MU of a communicating equipment is equipped with a called condition recording function 1 to record the reason information included in a message received in an ISDN layer 3 and a redialling conditions setting function 2. The redialling conditions setting function 2, when the discharging of a line is completed without performing the line connection, is the function to decode the reason information recorded by the called condition recording function 1 and count the redialling interval and the redialling frequency. When the line cannot be connected with the opponent to send a call setting message, the redialling processing is performed in accordance with the redialling conditions counted by the redialling conditions setting function 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic redial system for executing a redial process again after a certain period of time when a communication device cannot connect to a line to which a call setting message is sent and the line is not connected. It is a thing.

[0002]

2. Description of the Related Art In a recent communication device such as a telephone or a facsimile machine, if a call process is executed but a line connection is not possible due to the state of the communication network or the device of the called user, the call process is executed after a certain period of time. Those equipped with an automatic redial function that activates the redial process are in widespread use.

However, there are various cases in which the line cannot be connected, for example, when the communication network or the called user device is out of order, when the called user is talking, or when the called user is away.

The time required to return to the line connectable state differs depending on the case. For example, if the state is during a call by the called user, it may be possible to recover in a relatively short time. However, in general, when the state of the device or the like is out of order or out of service, It often takes a long time to return.

Therefore, when the calling process is executed by the automatic redial function, the interval of repeating the redial process (hereinafter referred to as the redial interval), the number of times the redial process is repeated (hereinafter referred to as the redial number), etc. It is desirable to be able to set according to the state of.

[0006]

However, most of the automatic redial functions provided in conventional telephones and the like are based on the premise that communication is performed by a public network, which is an analog line. The fact that the other party is in a call can be detected by detecting a busy tone (busy tone) sent from the public network, but it can be detected for other states such as a malfunction of the destination user device. Can not do it.

Therefore, in the conventional automatic redial system, the user or the like has previously set appropriate values for the redial interval and the number of redials in the communication device.

Therefore, even if the called user equipment is out of order and it takes a long time to recover, the call setup message is repeatedly sent uselessly at the preset redial interval and the number of redials. There was a problem that it became long.

Further, since the redial interval and the number of redials cannot be set according to the destination user or the state of the communication network, the set redial interval is too long and the communication processing is delayed, so that timely connection cannot be expected. There was also a problem.

The present invention has been made in view of the above circumstances. It is possible to automatically set the redial interval and the number of redials to an optimum value according to the state of the partner device, and to execute transmission of a call setting message. It is an object of the present invention to provide an automatic redial system capable of shortening the invalid hold time of the line while at the same time expecting a timely line connection.

[0011]

In the automatic redial system according to the present invention, it is indispensable to equip the control unit of the communication device connected to the ISDN with the called state recording function and the redial condition setting function.

Here, the called state recording function is a function of recording the reason information included in the message received in the ISDN layer 3, and the redial condition setting function cannot complete the line release because the line cannot be connected. In this case, the reason information recorded by the called state recording function is decoded, and based on the decoding result, the interval for repeating the redial processing and the number of times for repeating the redial processing are calculated.

When the line to which the call setup message is transmitted cannot be connected to the line, the redial process is repeated according to the redial conditions calculated by the redial condition setting function.

[0014]

In the automatic redial system according to the present invention, ISD
When the state of the communication network and the device of the destination user is detected from the reason information included in the disconnection or release of the N layer 3 or the release completion message, and the redial process is performed according to the state of the device of the communication network and the destination user. The redial interval and the number of redials can be set automatically, and timely connection can be expected, and at the same time, it becomes possible to shorten the invalid hold time of the line.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 3 is a block diagram of a digital exchange system implementing one embodiment of the present invention. As shown in FIG. 3, this digital exchange system includes a switch circuit TSW and extension telephones TEL1 to TE connected to the switch circuit TSW via line circuits LC1 to LCn.
Ln and the switch circuit T via the line circuit LCM
Relay stand ATT connected to SW and external communication line CO
The external line trunks COT1 to COTm connecting 1 to COm to the switch circuit TSW and the control unit (central processing unit unit) MU are provided.

Here, the control unit MU includes the above-mentioned switch circuit TSW and line circuits LC1 to LCn, LCM.
Also, it is a central part of the digital exchange system that controls the operations of the external line trunks COT1 to COTm, and also has a function for carrying out one embodiment of the present invention. The details of the configuration will be described later.

In the extension telephones TEL1 to TELn,
As shown in the figure, a so-called button telephone having an outside line selection key and a single telephone without an outside line selection key coexist, but in this digital exchange system, both the button telephone and the single telephone can be used as a relay stand. ATT
Also in this case, the automatic redial process according to the embodiment of the present invention can be used.

The external communication lines CO1 to COm mentioned above include those of analog lines and those of ISDN lines as shown in the figure. To utilize the automatic redial process according to one embodiment of the present invention, Only when making a call using the ISDN line.

In the control unit MU, as shown in FIG.
A central processing unit CPU and a memory device M managed by the central processing unit CPU are provided. Here, the memory device M is a readable / writable storage device using a RAM, an EPROM or the like, and information and programs required for redial processing are loaded together with information and programs required for operation control of each circuit in the system. ..

The central processing unit CPU of the control unit MU is
As shown in FIG. 1, in order to carry out an embodiment of the present invention, a called state recording function 1 and a redial condition setting function 2 are provided.
And a redial execution function 3, and the memory device M has a reason information storage area 5 and a redial interval storage area 6 in order to execute an embodiment of the present invention.
And a redial number storage area 7 are set.

The called state recording function 1 is used in the ISDN layer 3 when a call setup message (SETUP) is sent from an extension telephone or the like in the system using an ISDN line (that is, a call is made). Communication network (I
This is a function of detecting the reason information included in the disconnection message (DISC) from the SDN line) and recording the detected reason information in the reason information storage area 5 of the memory device M.

In communication using ISDN, it is possible to receive a service of notifying the reason information indicating the state of the line or the state of the partner device by the reason display number. As a specific example, the reason display number # 17 means “destination user busy”, # 19 means “destination user calling”, # 22.
Means "change the other party's subscriber number", # 27 means "the partner terminal is out of order", # 38 means "a network failure that seems to last for a relatively long time", and # 41 means "you can expect an immediate recall." The call status can be confirmed by being notified of these reason display numbers.

The redial condition setting function 2 is
When the line connection is not established to the other party who has sent the call setup message (SETUP) and the line release is completed (that is, when REL_COMP is received), the reason information recorded by the called state recording function 1 is displayed. It is a function of decoding and calculating the redial interval (the interval at which the redial process is repeated) and the number of redials (the number of times the redial process is repeated) based on the decoding result.

The reason information when the line cannot be connected is sorted and classified in advance for each prescribed reason display number, and the redial condition setting table in which the optimum redial interval and the number of redials are given to each reason information is given to each reason information in the memory. It is stored in the device M. Redial condition setting function 2
Shall calculate the optimum redial interval and the number of redials with reference to this redial condition setting table.

The redial execution function 3 is a function for executing redial processing based on the result calculated by the redial condition setting function 2.

According to one embodiment of the present invention, when a call setup message is transmitted using an ISDN line and the line is released without being able to connect to the called user, the functions 1, 2, 3 described above are completed. Is used to repeatedly execute the redial process after a fixed time after receiving the release completion message.

The extension telephone TEL of the system shown in FIG.
The processing procedure of one embodiment of the present invention will be described by taking as an example the case where a call setup message is sent from the second station using the ISDN line CO2.

FIG. 2 shows a processing procedure in one embodiment of the present invention. First, an extension telephone (TEL2).
Sends a call setup message (SETUP) using the ISDN line CO2 ((A) in the figure). For a call setup message, usually a call confirmation (CALL_PRO
C) is returned.

Next, when the communication network (ISDN line) notifies the system of a disconnection message (DISC) accompanied by appropriate reason information #n because the other party is busy, the called state recording function 1 operates. The reason information #n in the disconnection message is stored in the reason information storage area 5 of the memory device M.
It is stored in the corresponding location of the extension telephone TEL2 in (1) in the figure.

In this case, the user of the extension telephone TEL2 disconnects once, knowing that the other party is blocked by the notification of the detected reason information #n or the busy tone ((C) in the figure).

Then, the redial condition setting function 2 and the redial execution function 3 are activated, and the redial condition setting function 2 decodes the reason information #n recorded by the called state recording function 1 and follows the reason information. The calculated redial interval (T) and redial count (N) are stored in the redial interval storage area 6 and the redial count storage area 7.
In accordance with the calculation result of the redial condition setting function 2, the redial execution function 3 repeats the transmission of the call setting message at regular time intervals.

In FIG. 2, reference symbol T is a redial interval set by the redial condition setting function 2, and RD1 and RD2 are redial processes. The number of executions of the redial process is counted, and when the number of times set by the redial condition setting function 2 is executed without connecting the line, the automatic redial process ends there. On the other hand, when the line connection is successful before the redial process is repeated the set number of times, the automatic redial process ends at that point.

In the automatic redial method of the embodiment described above, the ISDN layer 3 disconnection message (DIS
The state of the communication network and the device of the called user is detected from the reason information posted in C), etc., and the redial interval and the number of redials during redial processing are automatically performed according to the state of the device of the communication network and the called user. It became possible to expect a timely connection, and at the same time, it became possible to reduce the invalid hold time of the line.

The apparatus to which the present invention is applied is not limited to the digital exchange system described above. The present invention can be applied to a general ISDN terminal connected to an ISDN line (for example, a telephone for ISDN or an image communication device).

Further, in the above-described embodiment, the redial condition setting function and the redial execution function are automatically activated after the line is disconnected. Whether or not to activate the condition setting function and the redial execution function may be selected by the caller using a switch or the like provided on the telephone.

Further, in the present invention, the message on the layer 3 which is the target for detecting the reason information is not limited to the disconnection message of the above-described embodiment. The reason information may be detected from the call confirmation or the release completion message.

[0037]

As is apparent from the above description, in the automatic redial method according to the present invention, the disconnection or release of ISDN layer 3 or the reason information contained in the release completion message indicates the communication network and the destination user's device. It is possible to detect the status and automatically set the redial interval and the number of redials when performing redial processing according to the status of the communication network and the device of the called user, and it is expected that timely connection can be expected. At the same time, it became possible to shorten the invalid hold time of the line.

[Brief description of drawings]

FIG. 1 is a functional explanatory diagram of a main part of a communication device that executes an embodiment of the present invention.

FIG. 2 is an explanatory diagram of processing according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a communication device that executes an embodiment of the present invention.

[Explanation of symbols]

 1 Called state recording function 2 Redial condition setting function 3 Redial execution function 5 Reason information storage area 6 Redial interval storage area 7 Redial count storage area MU control unit CPU central processing unit M memory device

Claims (1)

[Claims] 1. An automatic redial method in a communication device connected to an ISDN, wherein a redial process is performed again after a fixed time when the line to which the call setting message is sent cannot be connected to the other party. Therefore, the control unit of the communication device has a called state recording function for recording the reason information included in the message received in the ISDN layer 3, and the line reception is completed when the line release is completed because the line connection cannot be established. Equipped with a redial condition setting function that decodes the reason information recorded by the call status recording function and calculates the interval for repeating the redial process and the number of times the redial process is repeated based on the result of the decoding. A feature that repeats the redial process according to the calculated redial conditions. Redial method.