Call back when not engaged by means of automated redialling in communication networks

The present invention relates to a method for automated redialing of a telephone number in telecommunications networks in the case of a called subscriber idle signal.

In current telecommunications networks, attempts to make telephone calls that are not answered are lost as long as the called subscriber does not have the mailbox service enabled. The calling subscriber is only allowed to make further attempts to call at a later date.

Telephone networks know telephone terminals or devices which attempt to automatically reconnect by automatically dialing the last subscriber number dialed after a certain period of time. However, the redial function is only active when the called party's line is busy. Moreover, only ISDN terminals and higher-end telephone devices have such an automatic recall function. Similar functions are also known in cellular networks or in cellular terminal equipment.

All these functions enable automatic recalling only when the subscriber's line is busy.

In ISDN networks, there is indeed the "Recall on no answer service, when subscriber A tries to page subscriber B but subscriber B does not answer the paging." If the "Recall on no report" function is activated, automatic redialing is only started when subscriber B is active again, ie when his phone is used again and the subscriber is making a call, for example.

The disadvantage of such a solution is that the service only starts working after the called subscriber B resumes telephone activity.

The object of the invention is to provide such a method for automatically performing redialing on line idle signal of a called subscriber in telecommunications networks, which allows automatic redialing when subscriber B does not answer the telephone, even though his telephone was turned on, was within the network range and was making calls.

This goal is implemented according to the invention, which consists in the fact that when calling the subscriber, the signal with the subscriber's number and the signal with the calling subscriber's number are temporarily stored in the telephone exchange, and then, after the call is terminated, due to the signals sent from the calling subscriber's cell phone, the telephone exchange automatically sends signals to the called subscriber at specified intervals and within a specified time interval, to perform automatic redials.

When the called subscriber answers, the telephone exchange preferably sends back signals to the calling subscriber to establish a connection between them.

In the event that the called subscriber fails to answer the call, the telephone exchange preferably sends back a signal to the calling subscriber, as a result of which he is informed that the called subscriber has not responded within a certain period of time, after which call repetition is interrupted.

The predetermined intervals and time intervals of the signals sent to the subscriber called by the switchboard are preferably freely configurable by the calling subscriber.

The method according to the invention means for the subscribers of the telecommunications network an increase in the comfort of using the telephone. Thanks to the application of the invention, instead of manual redialing, and above all, the necessity to make another attempt to establish a connection with the called subscriber, it is possible to automatically attempt to carry out the calls until the subscriber answers the phone, but until the previously set limit of calls is over. This type of automatic connection is performed by an end device via the switchboard.

The essence of the invention is a solution constituting a new service of calling from one telecommunications network to other networks, in particular from radio and fixed networks, in order to result in an initially ineffective conversation with the subscriber.

After successive paging attempts in which the called subscriber does not answer the call, the telephone exchange according to the invention triggers, at the request of the calling subscriber, at specified time intervals and at specified intervals, e.g., every fifteen minutes in the next ninety minutes, to automatically redial the subscriber. Generally, attempts by the switchboard to call are made with short answer times in order to avoid possible inconvenience to the called subscriber.

In the case of automatic dialing, when the subscriber answers, the calling subscriber is alerted with a calling tone, i.e. as if he had been called himself, that the expected call was successful. In order to cover the time necessary to call the calling subscriber, information can be recorded for the use of the called subscriber, eg “Please wait, the connection will be made soon. If the calling subscriber does not answer the call or the called subscriber hangs up in the meantime, the procedure is aborted.

If the called subscriber fails to answer within a time interval of, for example, ninety minutes, the procedure is also aborted. The calling subscriber is then informed that the called subscriber is not reachable. The calling subscriber may be informed by means of a specific audio signal, a short text message (SMS) or a voice message.

The redial service by a switchboard can in principle be activated or deactivated by the calling subscriber, in particular by selecting the appropriate service number. Also freely configurable and editable may be envisaged, i.e. possibility to set the time interval for redialing or the time interval for dialing attempts. Other customer service interfaces are also possible, e.g. activation and configuration via the Internet, calling via the network operator's hotline, entering the "direct service activation code, by fax, etc."

In order to be able to use the previously activated Recall in case of no answer service when used, i.e. with the next unsuccessful call, it is necessary to use the keyboard, which is used by the subscriber, just like in the case of the well-known "Recall on busy tone" service. starts the procedure after hearing one or more no-answer signals. The telecommunications network could support the subscriber in such a way that it starts automatically after a certain time, e.g. after 30 seconds - assuming that the service has been previously activated - a message containing a key code, e.g. * 38 # + redial key, to start the service. It is also possible to transmit a specific key code to the telecommunications network, e.g. * 38 # + redial key, only after the end (no) conversation, i.e. after hanging up. In such cases, the telecommunications network would have to memorize the last dialed number of the called subscriber for this purpose.

This service can be configured and edited in a similar way. The subscriber selects, for example, the sequence of the * 38 # keys again, and the system offers him - after a specified waiting time, during which he waits for the redial key to be triggered - appropriate menu-driven options (voice or key). So, for example, the sequence of * 38 # 120 # 90 # 5 # could mean that the recall, in the event of an idle signal, would start in 120 minutes and would be repeated as described for the next 90 minutes every 5 minutes.

Apart from the advantageous solution based on the service of a telecommunications exchange, it is also possible to use an advantageous solution by using an end device. The cellular terminal may recognize when the called subscriber does not accept the call and, for example, initiate automatic redialing and / or offer the calling subscriber suitable voice or key control capabilities. This solution requires the production of end devices specifically designed for this purpose.