JPH01248741A - Call reception limit system - Google Patents

Abstract

PURPOSE:To prevent overload when an exchange is busy by providing an unended call number counter for each digital subscriber line to an electronic exchange and sending a call restriction message to a digital subscriber line dialing unended calls of a prescribed number or over within a prescribed time so as to extend the redial interval of a terminal set with an automatic redial function. CONSTITUTION:An ISDN terminal set A11 (B12) with an automatic redialing function repeats redialing till a call is connected at a redial interval tS unique to the terminal set itself if the own call is busy. On the other hand, the elec tronic switching equipment 1 is provided with a counter counting unended call number for each digital subscriber line and when the count exceeds the upper limit predetermined within a prescribed time, the electronic switching equipment 1 sends a call restriction message to the digital subscriber line. When the termi nal set A11 or B12 receives a call restriction message, the terminal set extends its internally provided redialing interval tS into a redialing interval tL at the restriction. Thus, the overloading of the electronic switching equipment 1 is relieved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a call acceptance restriction system, and in particular to an automatic re-call I
I that accommodates SDN terminals via digital subscriber lines
This invention relates to a call reception restriction method for an electronic exchange for SDN.

[Conventional technology]

Conventionally, this type of call acceptance restriction system has been considered for non-automatic re-calling terminals, and when the exchange restricts the acceptance of calls, the exchange sends a busy tone back to the terminal, or an announcement machine makes an announcement. There are ways to send it back.

[Problem that the invention seeks to solve]

Since the above-mentioned call acceptance restriction method is intended for non-automatic re-calling terminals, if an ISDN terminal with an automatic re-calling function encounters a busy call, it will immediately repeat the call. As the number of calls increases, the number of invalid calls due to re-calls during times of congestion increases rapidly, resulting in further overload of the exchange, which is a drawback.

[Means for solving problems]

The call reception restriction method of the present invention is applicable to an ISDN terminal having an automatic re-calling function and an ISDN terminal that accommodates this ISDN terminal.
In the electronic exchange for DN, this electronic exchange calculates the number of incomplete calls from the ISDN terminal.
The count is counted for each digital subscriber line to which the terminal is connected, and when this counted value exceeds a preset value within a preset time, a call restriction message is sent to that digital subscriber line, and the ISDN When the terminal receives the call restriction message, the terminal is configured to set the re-call interval in the automatic re-call function to a separately set long interval only once.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Figure 1 is a sequence diagram of an example of a signaling message in the case of an incomplete call between an electronic exchange and an ISDN terminal with an automatic re-calling function, and Figure 2 is a sequence diagram of an example of an electronic exchange to which item 1- is applied. This is a configuration diagram showing an example of an I SDN terminal, and the electrical and logical specifications of the signaling system of the digital subscriber line between the network termination device 2 of the electronic exchange 1 and terminals A, BLL, and 12 are based on CCITT's I series. This is in accordance with the recommendations.

In Fig. 1, if the ISDN terminal A or Bll or 12 with automatic re-calling function becomes busy, the terminal will wait for the terminal's own re-call interval ts until the call is connected. Repeatedly call again.

On the other hand, a counter is provided in the electronic exchange 1 to count the number of incomplete calls for each digital subscriber line, and if the counter exceeds a predetermined upper limit within a certain period of time, the digital subscriber The electronic exchange 1 sends a call restriction message to the line.

Terminals A and B ], 1 and 12 are equipped with receivers for outgoing call restriction messages, and when they receive the outgoing call restriction message, the automatic recall function changes the internal recall interval 1 s to the restricted recall interval tL. Change the extension to . However, after the re-call after the change, the re-call interval returns to the original re-call interval ts.

The above operation reduces the overload on the electronic exchange 1.

〔Effect of the invention〕

As explained above, the present invention provides an electronic exchange with a counter for the number of incomplete calls for each digital subscriber line, and checks whether a digital subscriber line that has made a certain number or more of incomplete calls within a certain period of time is Since a restriction message is sent and the re-call interval of a terminal with an automatic re-call function is extended, it is possible to prevent overload during switching exchange congestion.

[Brief explanation of the drawing]

FIG. 1 is a sequence diagram of an embodiment of a signaling message in the case of an incomplete call according to the present invention, and FIG. 2 is a configuration diagram showing an example of an electronic exchange and an ISDN terminal to which the invention of FIG. 1 is applied. be. 1...Electronic exchange, 2...Network termination equipment, 11.12
ISDN Kosue Senju Kukan l Ikuhaya 21! r

Claims (1)

[Claims] In an ISDN terminal having an automatic re-call function and an ISDN electronic exchange that accommodates this ISDN terminal, this electronic exchange calculates the number of incomplete calls made from the ISDN terminal for each digital subscriber line to which the ISDN terminal is connected. and when this counted value exceeds a preset value within a preset time, a call restriction message is sent to the digital subscriber line, and when the ISDN terminal receives the call restriction message, A call reception restriction method characterized in that the re-call interval in the automatic re-call function is a long interval that is set separately.