WO1998021900A1

WO1998021900A1 - Method and arrangement for call forwarding in intelligent network

Info

Publication number: WO1998021900A1
Application number: PCT/FI1997/000674
Authority: WO
Inventors: Vesa-Pekka Nikula; Niko LINDSTRÖM; Kalevi Ahola
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1996-11-08
Filing date: 1997-11-06
Publication date: 1998-05-22
Also published as: FI964510A0; AU4870297A; FI104778B; FI964510L

Abstract

The invention relates to a method and an arrangement for making a telephone call from a calling terminal to a called terminal, wherein said call to the called terminal is forwarded to another destination in a telephone system. The call terminal destination is changed to be another destination and the information of said another destination is transferred into an intelligent network means connected to the network by means of a call forwarding message. The call forwarding operation is controlled by the intelligent network means.

Description

METHOD AND ARRANGEMENT FOR CALL FORWARDING IN INTELLIGENT NETWORK

FIELD OF THE INVENTION

The present invention relates to methods for call forwarding. The invention relates further to an arrangement for performing call forwarding operations.

BACKGROUND OF THE INVENTION

In the present call forwarding systems the call forward feature is activated by setting the telephone terminal in an off-hook state, subsequently pressing an appropriate call forward button or key, entering the desired number to which the call is to be forwarded and finally setting the terminal in an on-hook state. PBXs (Private Branch Exchanges) will thus get the instructions to transfer the call to another number and the necessary information about that new number. The transfer of calls from one terminal to another is realized by arranging an IN (Intelligent Network) switch in the network to recognize a transfer request, initiate the call to the desired terminal and then to bridge the incoming call to said terminal while dropping the call to the original terminal. Said IN is per se known by the skilled person, and is described in more detail eg. in ITU-T publications series Q.1200 (International Telecommunication Union - Telecommunication Standardization Sector) which are incorporated herein as reference. The user of this feature might even be on a cellular (ie. mobile) telephone and like to forward the call to a telephone terminal connected to a fixed telephone line. The transfer is initiated when the user hits an appropriate key and dials a predetermined feature access code. The user is then prompted to enter the number of the desired terminal to which the call should be forwarded. If said terminal is busy or out of service, the call forwarding will fail and the call on hold is returned back to the user of the feature.

SUMMARY OF THE INVENTION

The above arrangement has some disadvantages, for instance in cases where a subscriber has two telephones which are connected to different networks, eg. one on a fixed line network and another in a cellular network, wherein the terminal used on the fixed line is an extension behind a certain PBX, such as a PBX for a private office and the terminal on the cellular network is an analog or a digital mobile telephone, such as a GSM, NMT or AMPS etc. telephone. When calling to the extension of the PBX, the call is routed to the PBX wherefrom it is further routed either to said extension or, in case the call forward is activated, to a number programmed in the PBX, eg. to a mobile telephone or to a fixed telephone which an extension of another PBX.

This kind of operation requires a lot of line resources due to the fact that the call has to be transmitted from a local exchange to the PBX and back to the local exchange to be transmitted to the predetermined call forward number. The capacity of the PBX may also run out, or the functions thereof may remarkably slow down due to the extreme load caused by the various call forward operations. In most cases there are also some additional costs involved since the call has to be transmitted twice between the PSTN exchange and the PBX and it may even have to be transferred to another network, such as to the mobile telephone network. These additional costs are usually charged from the subscriber of the PBX. The caller is liable only for similar charges as he or she would have if calling directly to the PBX.

When the call is forwarded to a mobile telephone network, there is usually a need for fixed connections or trunks between the PBX and the mobile network operator(s). In case the holders of the extensions under one PBX are using different competing mobile networks, there should be fixed connections to all of these from the PBX. The trunks between the PBX and the mobile phone network require maintenance. In case the forwarded calls are not connected directly from the PBX to the mobile phone network, this may lead to a remarkable charging by the fixed line network operator. This might be the case especially in occasions where the fixed PSTN and the mobile network are run by competing operators. Therefore it would be desirable to be able to use one operator for one call, to be able to connect the calls with minimum amount of transmissions and through a minimum amount of various telecommunication apparatus and to avoid situations were one single call is transmitted forth and back in trunks. A further existing problem is that the subscriber is liable for all of the costs caused by the call forwarding, and it would be desirable to transfer at least a part of these costs to the caller.

Therefore it is an object of the present invention to provide a new type of solution for call forwarding.

An object of the present invention is also to provide a method and arrangement in which an IN (Intelligent Network) switch and/or services is used for call forwarding.

It is also an object of the present invention to provide a method and an arrangement by means of which the caller initiating the call becomes liable for the additional costs which may be due from the call forwarding and by means of which said caller is enabled to select whether the call should be forwarded or not.

A further object of the present invention is to provide a method and an arrangement, by means of which the user of a telephone terminal may readily change the call forward data stored in an IN switch concerning that terminal.

It is also an object of the present invention to provide a method and an arrangement, by means of which the capacity requirements for a private network, such as an internal company network, are reduced.

It is also an object of the present invention to provide a method and an arrangement by means of which the costs for call forwarding are reduced.

A further object of the invention is to provide a method and an arrangement for controlling the call forwarding operations between various operators.

Other objects and advantages of the present invention will be brought out in the following part of the specification taken in conjunction with the accompanying drawings.

The objects are obtained by a method for making a telephone call from a calling terminal to a called terminal, wherein said call to the called terminal is forwarded to another destination in a telephone system. Said system includes terminals connected to the network including exchanges, switches and operational connections therebetween, said terminals being a part of a fixed network and/or a mobile network. Said system is further including intelligent network means for controlling and directing the calls to another destinations as dialled by the calling terminal. Said system is further including a plurality of network operators for allowing the terminals to have an access to the services of said networks. The inventive method comprises the steps of: changing the called terminal destination to be another destination and transferring the information of said another destination to said intelligent network means connected to the network by means of a call forwarding message, transmitting the telephone call from the calling terminal through at least one exchange of the destination network designated by an identification part of the called terminal destination number, directing said called incoming call to the intelligent network means by means of said at least one exchange in the route from the calling terminal to the called destination which is informed of said identification part indicating that the call is to be directed to the intelligent network means, changing said destination information of the called destination terminal to correspond said another destination designated by the intelligent network means, said another destination corresponding said information transferred to the intelligent network means by means of said call forwarding message, and transmitting the call to a destination indicated by said intelligent network means through a route arranged by at least one network operator controlling at least one of the networks.

According to an alternative embodiment the invention provides a method for making a telephone call from a A number to a B number, said B number being an extension of a PBX operationally connected to a PSTN through a PSTN exchange. Said method comprising the steps of transmitting said telephone call to said B number through an intelligent network switch means, said intelligent network switch means being operationally connected to said PSTN exchange, controlling the transmitting of said call from said intelligent network switch means to an extension number by said intelligent network switch means, said extension number being either said B number or any other telephone number provided in the intelligent network switch means by a call forwarding message, whereby the call will be connected to said PBX only in case said number provided by the intelligent switch means is said B number.

According to a preferred embodiment the arrangement in telecommunication systems comprises PBX means having a plurality of extensions operationally connected therein, each of the extensions having a B number, a PSTN exchange and intelligent network switch means operationally connected to the PSTN exchange. The arrangement is such that the incoming calls from a A number to the PBX means are transmitted from the PSTN exchange to the intelligent network switch means. The intelligent network switch means further comprise means for controlling a forwarding of the incoming call from said intelligent network switch means to a desired extension number set by a call forward message, said extension number being either said B number or any other telephone number provided in the intelligent network switch means by said call forwarding message, whereby the call will be connected to said PBX only in case said number provided by the intelligent switch means is said B number.

Several advantages are obtained by means of the present invention, since the solution provides a simple, reliable and controllable manner for call forwarding. The solution decreases traffic in exchanges and/or switches and thus reduces the requirements for the number and/or capacity thereof and the amount of trunks. The trunk lines are free to transmit only such calls where at least one terminal involved to that call is an extension of the PBX. The costs for call forwarding are reduced due to decreased amount of apparatus and less maintenance, and especially due to a possibility of avoiding unnecessary transmissions between various operators and/or switches. The telecommunication traffic in and out from a company can be controlled and operated by one single operator running the PSTN network.

In the following the present invention and the other objects and advantages thereof will be described by way of examples with reference to the annexed drawings, in which similar reference characters throughout the various figures refer to similar features. It should be understood that the following exemplifying description of the invention is not meant to restrict the invention to the specific forms presented in this connection but rather the present invention is meant to cover all modifications, similarities and alternatives which are included in the spirit and scope of the present invention, as defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures la and lb are schematic presentations of prior art solutions;

Figure 2 is a schematic presentation of an arrangement according to one embodiment of the present invention;

Figure 3 discloses schematically another embodiment of the present invention;

Figure 4 discloses an arrangement for controlling different operators in accordance with the present invention; and

Figures 5 and 6 are schematic presentations of a further alternative embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure la is a schematical presentation of a prior art solution. A call intented to reach an extension terminal 5 (...3171) of PBX 4 (01055...) is initiated by a subscriber A. The call is directed through a local exchange of a PSTN (Public Switched Telephone Network) and through a trunk line 3 to the PBX 4, which might be a switch of a private company or similar. However, the user (B) of said extension has forwarded the call to a telephone terminal which is a subscriber of another network (not shown, but connected to the PSTN) by giving instructions to the PBX 4. Thus the PBX transmits the call back through the trunk lines 3 to the local exchange 2 of the PSTN which in turn transmits the call through an appropriate route to said another network, which might even be run by another operator. Thus the call from the A number is first transmitted to the PBX and subsequently transmitted back from there, and might even be transmitted further to a different network, which all requires additional capacity from the trunk lines 3, the PBX 4 and the exchange 2 so as to be able to perform the call forwarding.

Figure lb discloses another prior art solution according to which the PBX 4 is provided with trunks to various mobile phone networks 6. A possibility for an international call to a telephone in a foreign network is also shown. There might be an additional exchange 7 between the PBX and the mobile network 6. A main exchange 1 of the PSTN network is connected to a local exchange 2 through an IN switch 8 which is arranged to control the transfers between various local exchanges and the operation thereof. As can be seen from Fig. lb, in case a call initiated by subscriber A is forwarded to a mobile terminal in network 6, it needs to be routed through several exchanges and switches and even from one network to another, which requires a lot of capacity and causes additional costs for the subscriber of the PBX.

Figure 2 discloses the main principles of the invention. PBX 4 may, for example, be a switch of a company and have a plurality of extensions 5, a terminal provided with number 010553171 in the example being one of the extensions, ie. the B number. The terminals can, of course, be of wireless or cordless type. An IN switch 10 is operationally connected to a local PSTN exchange 2. All incoming calls to the extensions of PBX 4 are transmitted to said IN switch means 10, as is indicated by an arrow from local exchange to the IN.

The phone numbers of the PBX (01055...) are stored in and controlled by the IN means 10. In other words, IN means 10 controls the incoming calls directed to that given PBX. For this purpose the IN switch means 10 comprises a table 12 of extension numbers B under the IN number of the company. The table comprises a section B for actual B numbers and section Cl for the activated numbers ie. for the numbers set by the subscriber B to be used in case of an incoming call. It is possible to arrange the setting of an appropriate number such that it can be performed by any telephone, for instance by using special codes for each subscriber B. Said table 12 may contain further sections, eg. C2, which will be activated in case Cl will not answer after a preset time, such as 20 seconds. The subscriber A initiates a call by calling to a PBX related B number, for instance to 010553171. This number includes an identification part 010, which notifies the exchange that the call is to be directed to the IN. Thus each such call is transmitted to the IN switch 10 in the PSTN instead of connecting them directly to the PBX 4. Said IN switch means controls the transmission of the call such that in case the set number in section Cl equals with B, the call will be forwarded to the PBX 4 through the dashed line and further to the terminal 5 at the office. However, in case the Cl number is different, eg. a mobile telephone number (05012345 in the example), the call will be forwarded to that number directly from the IN switch means 10 without any signals or transmissions to the PBX 4. Thus the trunk line 3 designated by a dashed line is only for calls from the extensions 5 of the PBX, and in some instances it may even be unnecessary.

Fig 3 is a schematic presentation of one further embodiment according to the present invention. In this case the IN switch means 10 is provided in connection with a main exchange 1 of the PSTN. As can be seen, the calls initiated by the A subscriber are routed through the main exchange 1 to the IN means 10, from which they are routed to an appropriate terminal through an appropriate route. The selection of a proper telephone number in the IN means 10 is similar to that disclosed in Figure 2, ie. the call forwarding operations are moved from the PBX to the IN switch means 10. However, in case the B number under the PBX 4 is deactivated, the call will be forwarded to eg. a mobile phone from the IN means 10 provided between the main exchange 1 and the local exchange 2, which in most cases means that they are transmitted from the main exchange 1 of the network.

According to one embodiment the subscriber changes the data concerning the terminals or network to which his or hers calls should be forwarded by making a phone call to the IN switch means 10 and giving a predetermined code by the telephone, either by the telephone on the extension or by other telephone, such as his or hers mobile phone, to the IN switch means 10. According to one alternative way of updating the call forward data the IN switch means 10 controls even the calls made by the subscriber of the B number. In case the subscriber calls from another telephone terminal as in the previous time, the IN switch means 10 will automatically change the data, ie. the Cl section of the table 12, to correspond that specific terminal.

Figure 4 discloses an arrangement by means of which the owner of the PBX 4 is enabled to control the overall handling of the calls handled by various operators 6. The PBX includes a large amount of outgoing lines which are connected directly to the networks of a plurality of operators (three in the example). The owner of the PBX has determined how to choose a most suitable operator, for instance based on charging rates or other reasons. However, it is reasonable for each operator to have a right to route the call coming to the PBX in accordance with the present resources of the network. As a call forwarding has this far occurred in the PBX, the operator did not have any change to control how the call is routed as it was solely a decision made by the PBX, eg. on grounds of economical reasons. However, by providing an IN 10 to at least one network of at least one operator in accordance with the principles of the invention it is possible to provide a control means for call forwarding operations such that an operator is enabled to control the traffic in the network and to distribute the traffic in an appropriate manner. There may, for instance, occur situations where it is wise to direct the calls to a network of another operators, eg. due to a risk of overload. This kind of arrangement enables the operator to decide of how the network is used despite the direct connections from a large PBX.

Figures 5 and 6 disclose situations in which the call is forwarded from a "home telephone" ie. from a telephone which is not an extension of a PBX. The caller (A-subscriber) calls to a telephone terminal 5 controlled by call forwarding. The call comes in to the home exchange 2 of the called person. The exchange has marked the line to the destination by a mark which affects the call to be directed to the IN or by activating absent subscriber service (ASU) or a subscriber class which is the ASU which is a service which can be ordered to the home exchange. The IN will thus be contacted.

Due to the fact that there will be extra costs for the call forwarding, eg. since the call may be transferred to another network and even to abroad, the IN service will inform the caller of this extra charge and asks for a confirmation whether the caller is ready to pay this or not. If the caller confirms the extra charge, the call will be transferred to the destination given to the IN service by the B-subscriber. By means of this the B-subscriber avoids from extra charges caused by call forwarding, which charges could otherwise be remarkable. However, if the line is busy or the destination will not answer, no charges will be billed.

The IN 10 may be in implemented within the exchange or only a part of the functions thereof are implemented within the exchange.

In the examples of figs. 5 and 6 the A subscriber calls to number 2995867. The B subscriber has informed the IN through the home exchange of the new destination C, which is to be accepted or denied by the caller A. In case the caller decides to continue, the call will then be routed in accordance with the intelligent control of the home exchange to the other networks 6, such as mobile networks, foreign networks or other networks. In case the call is forwarded to a destination which is operated by the same operator and in the same network, it might not be necessary to add any extra charges and thus to present any requests for the confirmation.

It is to be noted that the invention can also be utilized in connection with mobile telephones. In case the called person is abroad, the mobile telephone roames to the foreign network and the HLR (Home Location Register) in the home country is updated accordingly. The calls will be forwarded to the network of that foreign operator. The HLR is connected to the IN and the incoming call will be transferred to the IN, which then asks whether the caller will pay for the transfer or not. If the answer is yes, the call will be forwarded in a known manner to the foreign destination from the IN and the caller A will be charged accordingly.

Thus, the invention provides an apparatus and a method by which a significant improvement can be achieved in the area of call forwarding. Benefits are especially obtained in field of forwarding calls directed to an extension of a PBX and in field of charging the actual caller. The use of the arrangement according to the present invention will provide remarkable savings for the subscribers having a PBX with several extensions due to the fact that those calls, in which the receiving person is not present at the fixed line terminal B and who has thus set a call forwarding feature on, will never enter to the switch ie. the PBX of the company or similar. Savings can be expected especially in occasions where the same operator runs both the fixed and the mobile telephone network.

It should be noted that the foregoing examples of the embodiments of the invention are not intended to restrict the scope of the invention defined in the appended claims.

Claims

1. A method for making a telephone call from a calling terminal to a called terminal, wherein said call to the called terminal is forwarded to another destination in a telephone system, said system including terminals connected to the network including exchanges, switches and operational connections therebetween, said terminals being a part of a fixed network and/or a mobile network, said system including intelligent network means for controlling and directing the calls to another destinations as dialled by the calling terminal, said system further including a plurality of network operators for allowing the terminals to have access to the services of said networks, the method comprising the steps of: changing the called terminal destination to be another destination and transferring the information of said another destination to said intelligent network means connected to the network by means of a call forwarding message, transmitting the telephone call from the calling terminal through at least one exchange of the destination network designated by an identification part of the called terminal destination number, directing said called incoming call to the intelligent network means by means of said at least one exchange in the route from the calling terminal to the called destination which is informed of said identification part indicating that the call is to be directed to the intelligent network means, changing said destination information of the called destination terminal to correspond said another destination designated by the intelligent network means, said another destination corresponding said information transferred to the intelligent network means by means of said call forwarding message, transmitting the call to a destination indicated by said intelligent network means through a route arranged by at least one network operator controlling at least one of the networks.

2. A method according to claim 1, wherein said calling terminal is asked to confirm whether the call should be forwarded to said another destination or not.

3. A method for making a telephone call from a A number to a B number, said B number being an extension of a PBX operationally connected to a PSTN through a PSTN exchange, comprising transmitting said telephone call to said B number through an intelligent network switch means, said intelligent network switch means being operationally connected to said PSTN exchange, controlling the transmitting of said call from said intelligent network switch means to an extension number by said intelligent network switch means, said extension number being either said B number or any other telephone number provided in the intelligent network switch means by a call forwarding message, whereby the call will be connected to said PBX only in case said number provided by the intelligent switch means is said B number.

4. A method according to claim 3, wherein said intelligent network switch means comprise a table of the extension numbers, wherein one section of the table is for said B number and a further section or sections linked to said one section is for a number or numbers to which the incoming call is to be forwarded, and wherein said further section is updated by said call forward message.

5. A method according to claim 3 or 4, wherein the incoming call is transmitted to at least one mobile telephone network through an fixed connection between said intelligent network switch means and said at least one mobile telephone network.

6. A method according to any of claims 3 - 5, wherein the subscriber can change the call forwarding information stored in said intelligent network switch means by a telephone terminal operationally connected to said intelligent network switch means.

7. A method according to any of claims 3 - 5, wherein the call forwarding information stored in said intelligent network switch means concerning the B subscriber is changed by making a telephone call to any telephone number by a telephone terminal desired to be used for the incoming calls, the arrangement being such that the intelligent network switch means will automatically be updated such that the next incoming call to said B number will be forwarded to that telephone terminal.

8. A method according to any of the preceding claims, wherein the control of selection of network to be is handled by the operator providing the intelligent network services.

9. A method according to any of the preceding claims, wherein the calling terminal is charged from the forwarding of the call from the called terminal to the destination terminal.

10. An arrangement in telecommunication systems, comprising

PBX means having a plurality of extensions operationally connected therein, each of the extensions having a B number, a PSTN exchange, intelligent network switch means operationally connected to the PSTN exchange, the arrangement being such that the incoming calls from a A number to the PBX means are transmitted from the PSTN exchange to the intelligent network switch means, the intelligent network switch means further comprising means for controlling a forwarding of the incoming call from said intelligent network switch means to a desired number set by a call forward message, said extension number being either said B number or any other telephone number provided in the intelligent network switch means by said call forwarding message, whereby the call will be connected to said PBX only in case said number provided by the intelligent switch means is said B number.

11. An arrangement according to claim 10, wherein said intelligent network switch means comprise a table of the extension numbers, wherein one section of the table is for said B number and a further section or sections linked to said one section is for a number or numbers to which the incoming call is to be forwarded, said further section being updated by said call forward message.

12. An arrangement according to claim 10 or 11, wherein it further comprises fixed connection means between said intelligent network switch means and at least one mobile telephone network.

13. An arrangement according to any of claims 10 - 12, wherein the call forwarding information stored in said intelligent network switch means is arranged to be updated by a telephone operationally connected to said intelligent network switch means.