JPS6135745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for preventing infinite forwarding of incoming forwarded calls in a storage program controlled electronic switching system having a central processing control unit and a main memory.

Call forwarding refers to the automatic transfer of incoming calls to a subscriber to another subscriber specified by the subscriber based on a request from the subscriber.

Conventionally, an incoming call to a subscriber requesting call forwarding (hereinafter referred to as "subscriber A") is handled by switching resources (calls, trunk circuits, inter-office relay devices, etc.) The system was such that all data was transferred to the designated transfer destination subscriber (hereinafter referred to as subscriber B) as far as capacity allowed. Therefore, subscriber B is also a subscriber requesting call forwarding, and the designated forwarding destination is subscriber A.
If this is the case, the call will be repeatedly transferred between subscriber A and subscriber B, resulting in a serious drawback in terms of switching functionality, in that a large amount of valuable switching resources will be held ineffectively. was.
In particular, if subscriber B is accommodated in a different switching center than subscriber A, this will have the same negative impact on the extensive communications switching network.

An object of the present invention is to cause a central processing control unit to store control information regarding call forwarding status, which differs for each subscriber, in a main storage device for all call forwarding registered subscribers accommodated in the exchange; This information allows the central processing control unit to
A system is provided that solves the above-mentioned drawbacks by refusing call forwarding for new incoming calls to subscribers that are already being forwarded, and that realizes a call forwarding function that causes no practical problems. It's about doing.

That is, in the present invention, by storing control information regarding the call forwarding situation, which changes over time for each call forwarding registered subscriber, in the main memory, the central processing control unit is able to It is characterized by providing control information to determine the significance of call forwarding.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a basic system configuration diagram of the present invention,
It consists of a network (NW), a trunk circuit (TRK), a subscriber (SUB), a central processing control unit (CE), and a main memory (ME) that stores various information programs.

Figure 2 is a configuration diagram of the control information storage area in the main storage device. This area stores control information for all applicable subscribers, and in the initial state, all of the control information is "no longer in call forwarding". Information to the effect that "No"("0" in the example of FIG. 2) is stored.
Next, when the central processing control unit recognizes the incoming call to the subscriber, the central processing control unit refers to the control information corresponding to the subscriber (in the example of Figure 2, the contents of the ABC address). , if the call is not being forwarded, it issues a command to perform call forwarding and also sends control information corresponding to the subscriber to the effect that ``the call is already being forwarded''("1" in the example in FIG. 2). This information will be saved until the cancellation of the call is recognized.

Next, when the central processing control unit recognizes the arrival of a new call to the same subscriber in the call forwarding state, the central processing control unit uses the control information to indicate that the call is already being forwarded to the subscriber. At this point, the central processing control unit issues a command to reject call forwarding for the new call.

It should be noted that once call forwarding is completed, it is easily expected that the designated forwarding destination subscriber will normally be in a busy state until the call disappears. It can be said that this method does not reduce the quality of call forwarding service in any way compared to the above method.

As explained above, the present invention makes it possible to prevent call forwarding calls from being endlessly forwarded without degrading the quality of service.

[Brief explanation of the drawing]

FIG. 1 is a basic system configuration diagram in the present invention,
FIG. 2 is a configuration diagram of a control information storage area provided in the main storage device in FIG. 1. NW...Network, TRK...Trunk circuit,
SUB...Subscriber, CE...Central processing control unit, ME...
Main memory.

Claims (1)

[Claims] 1. In response to an incoming call to a subscriber accommodated in a stored program control type electronic exchange having a central processing control unit and a storage device, based on the specification of the subscriber,
In a call diversion system that automatically transfers the incoming call to another subscriber accommodated in the exchange or another exchange, updates over time regarding the transfer status of all call diversion requesting subscribers accommodated in the exchange. 1. A method for preventing infinite forwarding of a call forwarding call, characterized in that a call forwarding rejection condition is given to the central processing control unit by storing control information to be transferred in the storage device.