WO2007131269A1

WO2007131269A1 - System and method for communication

Info

Publication number: WO2007131269A1
Application number: PCT/AU2007/000633
Authority: WO
Inventors: Antonio Cantoni; John Frank Siliquini; Kevin Alston Fynn; Guven Mercankosk
Original assignee: Thebuzz Corp Pty Ltd
Priority date: 2006-05-11
Filing date: 2007-05-11
Publication date: 2007-11-22
Also published as: EP2022284A1; AU2007250519A1

Abstract

A system (1) that allows roaming cellular radio telephones (5) to communicate with remote telephony devices (8) using the Internet (10) or other suitable communications networks. The system includes one or more call bridges (4) that implement call legs (6,7) which can be bridged. The bridged call legs define a communications path between the roaming cellular radio telephone and the telephony device. Call bridges are selected under control of servers (2) so as to provide optimum call charges thereby mitigating costs and other factors related to the roaming nature of the cellular radio telephone.

Description

"System and Method for Communication"

Field of the Invention

This invention relates to a system and method for the telephone communication, particularly, although not exclusively for telephone communication using handheld cellular radio telephones ('mobile phones').

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Background Art

The use of handheld cellular radio telephones is well known. One of the advantages of the cellular radio telephones is that they are portable. As is well known, mobile phones are linked to a cellular radio network and use that network to communicate with other telephony devices. The networks that the mobile phones use to communicate and the tariffs paid for the use of the services available to the user depend upon which network service provider, and the level of service that users select. Advances in cellular radio telephone communications now mean that most users can take their mobile phones and use them within other networks - includes networks that are in other regions or countries. This is often referred to as 'roaming'. This functionality is facilitated through the use of 'roaming agreements' between cellular radio telephone network service providers in different locations. These agreements allow users to have access to the cellular radio networks, for example in different countries and to avail themselves of the functionality provided by these networks. The call tariffs associated with making and receiving calls whilst roaming varies from network to network, and also on the network service provider to which the Subscriber Identity Module (SIM) card of the 'phone is attached. However, these roaming call tariffs are most often much greater than the tariffs that would be charged if the same call was placed or received within the mobile phone's network service provider. In addition, charges are often incurred for receiving a call when roaming.

Attempts have been made to mitigate the high costs of these tariffs, for example through complex 'call back' arrangements or through the use of phone cards. However, these schemes do not provide the same seamless functionality provided when the phone is used 'at home' and necessitate the user to take extra steps. These schemes do not reduce call tariffs for receiving calls.

Even when mobile phones are used within the network owned by the network service provider, tariffs can be higher than normal for certain situations. For example, with some 'pre-paid' mobile phones on some plans, it may be cheaper to phone to some other countries than it is to phone a local number.

It should also be pointed out that if . a 'roaming' user uses a voicemail or messaging facility then this requires an international call to be made - to access the voicemail service in the user's 'home' country. The costs of doiηg this can be excessive.

Disclosure of the Invention

In accordance with a first aspect of the present Invention, there is provided a method of establishing communication in a communication system using at least one telephony device and at least one communications interface characterised in that it comprises

receiving and communicating call data to the at least one communications interface about a call initiated by a telephony device,

establishing communication between a communications facilitator and a first telephony device to identify said at least one communications interface to said first telephony device, and establishing at least a first call leg between said first telephony device and said at least one communications interface to allow access to communications data routed via said at least one communications interface.

Preferably, the call initiated by a telephony device is initiated by said first telephony device.

Preferably, receiving call data comprises receiving call data at said communications facilitator transmitted from said first telephony device, said call - data comprising a request for establishment of communication with a second telephony device.

Preferably, communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data from said communications facilitator to the at least one communications interface about a call initiated by said first telephony device.

Preferably, the method further comprises:

signalling said first telephony device to call said at least one communications interface to establish communication between said first telephony device and said at least one communications interface thereby establishing said first call leg.

Preferably, the method further comprises

establishing communication between the at least one communications interface and a second telephony device to establish a second call leg; and

coupling the first call leg and the second call leg at the at least one communications interface to thereby establish communication between said first telephony device and said second telephony device.

Preferably, said communications data routed by said communications interface comprises call data from said second telephony device. Preferably, the call initiated by a telephony device is initiated by a second ' telephony device.,

Preferably, the receiving call data comprises receiving call data at the at least one communications interface transmitted from the. second telephony device, said call data comprising a request for the establishment of communication with the first telephony device.

Preferably, communicating call data to the at least one communications interface about a call initiated by a. telephony device comprises communicating call data to the at least one communications interface about a call initiated by the second telephony device.

Preferably, the method further comprises

Preferably, the method further comprises establishing communication between the communication facilitator and the at least one communications Interface to transmit the call data to the communications facilitator from the at least one communications interface.

Preferably, the method further comprises identifying the at least one communications interface on the basis of the transmitted data received by the communications facilitator from the at least one communications interface.

Preferably, the method further comprises:

establishing a second call leg between the second telephony device and the at least one communications interface; and coupling the first and second call legs at the at least one communications interface to thereby establish communication between the first telephony device and the second telephony device.

Preferably, said communications data routed by said communications interface comprises call data from said second telephony device.

Preferably, the system includes a first communications interface and a second communications interface, and the call initiated by a telephony device is routed via the first and second communications interfaces, and wherein the first call leg is established between the first telephony device and the first communications interface, the method comprising:

coupling the first communications interface and the second communications interface to establish data communication therebetween;

establishing a third call leg between the second telephony device and the second communications interface; and

coupling the first and third call legs via the first communications interface and the second communications interface to thereby establish communication between the first telephony device and the second telephony device.

Preferably, the coupling of the first communications interface and the second communications interface is enabled by:

establishing communication between the communications facilitator and the second communications interface to communicate the identity of the first communications interface from the communications facilitator to the second communications interface;

establishing communication between the first communications interface and the second communications interface upon receipt by the second communications interface of the identity of the first communications interface. Preferably, the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral wfthin said single unit.

Preferably, the first communications interface and the second communications interface are provided remote from each other, and the method comprising:

establishing a fourth call leg between the first communications interface and the second communications interface prior to establishing the third call leg to couple the first communications interface and the second communications interface;

bridging the first call leg and the fourth call leg at the first communications interface; and

bridging the third call leg and the fourth call at the second communications interface, thereby coupling the first call leg and the third call leg via the first communications interface, the second communications interface and the fourth call leg to thereby establish communication between the first telephony device and the second telephony device.

Preferably, the call initiated by a telephony device is initiated by a second telephony device.

Preferably, receiving and communicating call data to the at least one communications interface about a call initiated by a telephony device comprises receiving call data from the second telephony device about the call initiated by the second telephony device and communicating the call data to the at least one communications interface about the call initiated by the second telephony device.

Preferably, the method further comprises establishing communication between the communication facilitator and the at least one communications interface to transmit the call data to the communications facilitator from the at least one communications interface. Preferably, the method further comprises identifying the at least one communications interface on the basis of the transmitted call data received by the communications facilitator from the at least one communications interface.

Preferably, said method further comprises storing audio or other multimedia information received from said second telephony device at said at least one communications interface, said audio or multimedia forming said communications data routed by said at least one communications interface.

Preferably, the method further comprises transmitting notification from said at least one communications interface to said communications facilitator of the storage of said audio or multimedia information.

Preferably, the method further comprises

Preferably, the method further comprises receiving a request at said at least one communications interface from said first telephony device for retrieval of said audio or multimedia information.

Preferably, the method further comprises transmitting said stored audio or multimedia information from said at least one communications interface to said first telephony device.

Preferably, the system includes a first communications interface and a second communications interface, and the call data relating to the call initiated by the second telephony device Is communicated to the first communications interface, the method further comprising: transmitting said stored audio or multimedia information from said first communications interface to .said second communications interface.

Preferably, the method further comprises transmitting notification from said first communications interface to said second communications interface of the storage of said audio or multimedia information.

establishing communication between the communications facilitator and the first communications interface to communicate the identity of the second communications interface from the communications facilitator to the first communications interface; and

establishing communication between the first communications interface and the second communications interface upon receipt by the first communications interface of the identity of the second communications interface.

Preferably, the method further comprises:

signaling said first telephony device to call said second communications interface to establish communication between said first telephony device and said second communications interface thereby establishing said first call leg.

Preferably, the method further comprises receiving a request at said second communications Interface from said first telephony device for retrieval of said audio or multimedia information.

Preferably, the method further comprises transmitting said stored audio or multimedia information from said second communications interface to said first telephony device. Preferably, the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral within said single unit.

Preferably, the first communications interface and the second communications interface are provided remote from each other.

In accordance with a second aspect of the present invention there is provided a communication system including at least one telephony device, at least one communications interface and a communications facilitator, wherein the at least one communications interface and the communications facilitator are arranged to communicate, said communications facilitator being operable to receive call data about a call initiated by a telephony device, and the communications facilitator being operable to communicate with a first telephony device to identify the at least one communications interface to said first telephony device, and

the at least one communications interface is arranged to receive communication from said first telephony device to enable access of communications data routed via said at least one communications interface.

Preferably, receiving call data comprises receiving call data at said communications facilitator transmitted from said first telephony device, said call data comprising a request for establishment of communication with a second telephony device.

Preferably, communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data from said communications facilitator to the at least one communications interface about a call initiated by said first telephony device. Preferably, the communications facilitator is operable to signal said first telephony device to call said at least one communications interface to establish communication between said first telephony device and said at least one communications interface thereby establishing said first call leg.

Preferably, the communications interface is operable to establish communication between the at least one communications interface and a second telephony device to establish a second call leg, and to couple the first call leg and the second call leg at the at least one communications interface to thereby establish communication between said first telephony device and said second telephony device.

Preferably, said communications data routed by said communications interface comprises call data from said second telephony device. ,

Preferably, the receiving call data comprises receiving call data at the at least one communications interface transmitted from the second telephony device, said call data comprising a request for the establishment of communication with the first telephony device.

Preferably, communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data to the at least one communications interface about a call initiated by the second telephony device.

Preferably, the communications facilitator is operable to establish communication between the communication facilitator and the at least one communications interface to transmit the call data to the communications facilitator from the at least one communications interface. Preferably, the at least one communications interface is identified on the basis of the transmitted data received by the communications facilitator from the at least one communications interface.

Preferably, the communications interface is operable to establish communication between the second telephony device and the at least one communications interface to establish a second call leg; and to couple the first and second call legs at the at least one communications interface to thereby establish communication between the first telephony device and the second telephony device.

Preferably, said communications data routed by said communications interface comprises call data from said second telephony device. ■

Preferably, the system includes a first and a second communications interface, and the call initiated by a telephony device is routed via the first and second communications interfaces and wherein the first call leg is established between the first telephony device and the first communications interface, and the first communications interface is arranged for coupling with the second communications interface, and the second communications interface is operable to establish a third communication leg with the second telephony device and the second communications interface such that coupling of the first and third legs via said first communications Interface and said second communications interface thereby establishes communication between the first telephony device and the second telephony device.

Preferably, the communications facilitator is in data communication wtth the second communications interface and is operable to communicate the identity of the first communications interface to the second communications interface such that the first communications facilitator is arranged to communicate with the first communications facilitator and to establish communication between the first communications interface and the second communications interface upon receipt by the second communications Interface of the identity of the first communications interface. Preferably, the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral within said single unit.

Preferably, the first communications Interface and the second communications interface are provided remote from each other, and wherein the second communications interface is operable to establishing a fourth call leg between the first communications interface and the second communications interface prior to establishing the third call leg to couple the first communications interface and the second communications interface, and wherein the first communications interface is operable to bridge the first call leg and the fourth call leg at the first communications interface, and the second communications interface is operable to bridge the third call leg and the fourth call leg at the second communications interface to thereby couple the first call leg and the third call leg via the first communications interface, the second communications interface and the fourth call leg to thereby establish communication between the first telephony device and the second telephony device.

Preferably, the at least one communications interface is arranged to storing audio or other multimedia information received from said second telephony device, said audio or multimedia forming said communications data routed by said at least one communications interface.

Preferably, the at least one communications interface is operable to transmitting notification from said at least one communications interface to said communications facilitator of the storage of said audio or multimedia information.

Preferably, the at least one communications interface is arranged to receive a request from said first telephony device for retrieval of said audio or multimedia information.

Preferably, the at least one communications interface is operable to transmit said stored audio or multimedia information from said at least one communications interface to said first telephony device. Prβferably, the system includes a first communications interface and a second communications interface, and the call data relating to the call initiated by the second telephony device is communicated to the first communications interface, the first communications interface being operable to transmit said stored audio or multimedia information from said first communications interface to said second communications interface.

Preferably, the first communications interface is operable to transmit notification from said first communications interface to said second communications interface of the storage of said audio or multimedia information.

In accordance with a third aspect of the present invention there is provided a cellular radio telephone for communication with a telephony device, the cellular radio telephone being operable, in response to a signal from a remote communications facilitator, to communicate with at least a first communications interface to establish a first call leg, the first communications interface being selectable by the. communications facilitator, whereby the at least a first communications interface is arranged for communication with the telephony device to establish a second call leg, and whereby the first call leg is bridged to the second call leg thereby establishing communication between the cellular radio telephone and the telephony device via the communications interface.

Preferably, the cellular radio telephone is arranged for communication with the call facilitator, and operable to transmit a request to the communications facilitator to establish communication with the telephony device, the cellular radio telephone being further operable, in response to a signal from the communications facilitator, to establish communication with the first communications interface thereby establishing the first call leg.

In accordance with a fourth aspect of the present invention there is provided a communications interface for use in establishing communication between a telephony device and a cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, and the communication between the cellular radio telephone and the telephony device comprise at least two call legs, wherein the communications interface is operable to bridge the at least two call legs to establish communication between the cellular radio telephone and the telephony device via the communications interface.

Preferably, the communications interface is arranged for communication with another communications interface to define a further call leg between said communication interfaces.

Preferably, the communications interface , is operable to store multimedia information received from the telephony device.

Preferably, the communications interface is further operable to transmit the multimedia, information to the first communications interface for storage therein, and the cellular radio telephone is operable to retrieve the stored multimedia information from the first communications interface.

In accordance with a fifth aspect of the present invention there is provided a communications facilitator for establishing communication between a telephony device and a cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, wherein the communications facilitator is operable to initiate communication between the cellular radio telephone and a first communications interface, thereby establishing a first call leg between the cellular radio telephone and the first communications interface, the communications facilitator being further operable to initiate communication between the first communications interface and the telephony device to thereby establish a second call leg, whereby the first call leg and the second call leg can be bridged to thereby establish direct communication between the cellular radio telephone and the telephony device via the communications interface.

Preferably, the communications facilitator is operable to receive a request from the cellular radio telephone to establish communication with the telephony device, and to transmit details of the request, in response to the request, to the first communications interface and to signal the cellular radio telephone to call the first communications interface, to thereby establish the first leg. Preferably, the communications facilitator is further operable to initiate a communication between the first communications interface and a second communications interface arranged for communication with a telephony device via third call leg, the communications facilitator being operable to transmit details of the first communications interface to the second communications interface so that the first and second communications interfaces can establish communications therebetween thereby establishing a fourth call leg, so that the first call leg and the fourth call leg can be bridged via the first communications interface, and the third call leg and the fourth call leg can be bridged via the second communications interface, thereby establishing direct communication between the cellular radio telephone and the telephony device via the first and second communications interfaces.

Preferably, the communications facilitator is operable to select the communications interface in accordance with predetermined conditions.

Preferably, the communications facilitator includes storage means for storing data relating to calls established between the cellular radio telephone and the telephony device.

Preferably, the communications facilitator is further operable to transmit a signal to the cellular radio telephone to communicate with the first communications interface to retrieve multimedia data therefrom.

In accordance with a sixth aspect of the present invention there is provided a data communication between a communications facilitator and a cellular radio telephone and at least one communications interface for enabling establishment of communication between a telephony device and the cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, wherein the data communication enables a communications facilitator to initiate communication between the cellular radio telephone and the first communications interface, thereby establishing a first call leg between the cellular radio telephone and the first communications interface, the data communication further enabling the communications facilitator to initiate communication between the first communications interface and the telephony device to thereby establish a second call leg, whereby the first call leg and the second call leg can be bridged to thereby establish direct communication between the cellular radio telephone and the telephony device via the communications interface.

In this way, by selecting the communications interfaces, mobile phone calls can be routed to the most appropriate call bridge to minimise call tariffs.

Other aspects of the invention involve maintaining various databases which are used to establish optimum service operating behaviour of the mobile phone and the system in general.

Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the following figures, of which:

Figure 1 schematically illustrates the architecture of an embodiment of a telephone communication system in accordance with a first aspect of the present invention;

Figure 2 schematically illustrates a first embodiment of the invention for the establishment of two call legs between a mobile telephone and a phone in a remote country using the system of Figure 1 where a roaming mobile is calling a phone in a remote country;

Figure 3 is a sequence diagram for the establishment of a call between a mobile telephone and a phone in a remote country as illustrated in Figure 2;

Figure 4 schematically illustrates a second embodiment of the invention for the establishment of three call legs between a mobile telephone and a phone in a remote country using the system of Figure 1 , where the phone in the remote country is calling the mobile telephone; Figure 5 is a sequence diagram for the establishment of a call between a mobile telephone that is being called by a phone in a remote country and as illustrated in Figure 4;

Figure 6 is a sequence diagram illustrating a third embodiment of the invention used for the recording and retrieval of voice messages by a roaming mobile phone 5 using the system of Figure 1 ;

Figure 7 is a schematic illustration of a fourth embodiment of the invention;

Figure 8 is a sequence diagram for a fifth embodiment of the invention, for the establishment of a call between a mobile telephone that is being called by a phone in a remote country and as illustrated in Figure 4; and

Figure 9 is a sequence diagram illustrating a sixth embodiment of the invention used for the recording and retrieval of voice messages by a mobile phone using the system of Figure 1.

Best Mode(s) for Carrying Out the Invention

Throughout the specification, unless the context requires otherwise, the word

"comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The term 'telephony device' is used herein to describe any device or apparatus that communicates within telephony environments: Examples are fixed landline phones, cellular radio phones, cordless phones, internet phones or any other such devices.

Figure 1 illustrates schematically the components of one embodiment of a system of the present invention. The system 1 comprises a call server 2, at least one call bridge 4, and at least two media gateways 3. It will be appreciated from the following description that other numbers of call servers 2 call bridges 4, and media gateways 3 can be used.

A roaming handheld cellular radio telephone 5 ('roaming mobile phone 5 ') is loaded with a software application which provides a mobile phone user interface thereby enabling the user to make and receive phone calls and voice mail messages. Preferably, the use of Java® can be used to write this software application, but other programming methods may also be used. The use of software applications, including those written in Java® is well known to persons skilled in the art and need not be described in any further detail herein. This application could be preloaded on the roaming mobile phone 5 or it could be loaded later, for example by downloading from a server. The downloading could be performed, for example, using the Internet and General Packet Radio Service (GPRS). When roaming, the roaming mobile phone 5 is located in a first country, A, and may wish to communicate with another telephony device 8 located elsewhere, for example in another country, B.

The mobile phone software application enables the roaming mobile phone 5 to communicate via a communications link 11 , for example using GPRS, Short Message Service (SMS)₁ or other low cost signalling method, with the call server 2 for the purpose of making or receiving phone calls to/from remote telephony devices. If required an internet access server 1 β can be provided to enable communications via the communications link 11. The software application is able to transmit/receive call details to/from the call server 2, such as - when making a call - details of the source of the call (usually that of a roaming mobile device wishing to place a call) and the destination phone number. The call server 2 uses this information and assists in establishing and receiving phone calls and voice mail messages between the roaming mobile phone 5 and other destination telephony devices. After receiving instructions from the call server 2, the software application is also responsible for initiating phone calls to directed call bridges 4 or other telephony devices 8. The mobile phone software application may also have features that detect calls to and from local (i.e. local to the country where the mobile is roaming) devices in order to allow the roaming mobile phone 5 to operate as it normally would.

The call server 2, under control of software, co-ordinates the establishment of phone calls between two telephony devices via the call bridges 4. The call server 2 will maintain a database which contains information regarding current call costs associated with multiple telephone service operators. This information is used to establish optimum service operating behaviour, for example by choosing which mobile operator to use within a roaming country so as to minimise call costs and/or for the making call bridge telephone number selection choices so as to minimise call costs, and/or determining if call divert options are cheaper than receiving a call outright, etc. This information is also signalled to the roaming mobile phone 5 whereby it will use this information to configure itself (under the control of the mobile phone software application) so as to establish optimum service behaviour of the mobile phone. The call server 2 also keeps a database of all system call bridges 4 and all their associated callable phone numbers. The call server 2 can also keep databases storing additional information such as customer preferences related to calls and voice mails and other databases that allow it to make decisions about setting up calls and voice mails. As mentioned above, the call servers 2 receive, messages via the communications link 11 ( for example, using GPRS, SMS, or other low cost signalling methods) from the roaming mobile phone 5 indicating the requirement for a new call establishment (either making or receiving a call) or retrieving a voice mail message. The call server 2 may also receive messages from a call bridge 4 (typically using the Internet Protocol over the Internet) indicating that a telephony endpoint wishes to make a call or leave a voice mail message to a roaming telephony device.

The system 1 will now be described further with reference to Figure 2. Phone calls consist of at least two call legs, a first call leg 7 from a source telephony endpoint (for example, the roaming mobile phone 5) to a nominated call bridge 4 and a second call leg 7 between a nominated call bridge 4 to a destination telephony endpoint 8. Additional call legs, between call bridges 4, can also be used to establish end to end calls. After receiving call details from the roaming mobile phone 5 or a call bridge 4, it is the function of the call server 2 to instruct the roaming mobile phone 5 via a communications link 11 (for example, using GPRS₁ SMS or other low cost signalling method) to initiate a call to a nominated call bridge 4 or other telephony device. It is also the function of the call server 2 to instruct the nominated call bridge 4 (typically using the Internet Protocol over the Internet 10) to initiate or receive a call between itself and a destination telephony device or another call bridge 4. The call server 2 can also include the functions associated with user authorisation, user current country location information, generation of user call detail records for billing, etc. In this regard, the call server 2 can include appropriate storage means (not shown) for storing data as required. There need only be one call server 2 for the system 1 to operate but there may be more than one for the purposes of reducing the signalling delay and/or scalability and/or redundancy purposes.

The telephony devices and roaming mobile phones 5 operate in conventional networks 9 such as PSTN and cellular radio telephone networks.

State Variables maintained at the call server 2 are as follows:

CALL_PROCEEDING_lιk - This variable indicates the state of establishing a call at call bridge 4 having an identifier CB/ and associated with a phone number NCB^ of call bridge 4. Valid states include IDLE, IN_PROGRESS, and FAILED. At system start-up this variable is initialised to IDLE for all call bridges 4.

CALLJD - Each call request to the call server 2 is given a unique call identifier.

Associated with each CALLJD is a unique and randomly generated TONEJD. A TONEJD is a sequence of one or more digits between 0 and 9

The call bridge 4, under control of software, is operable to receive or make call legs 6, 7 as instructed by the call server 2. It is also able to "bridge" call legs 6, 7 such that the phone call between a source telephony device - in this embodiment the roaming mobile phone 5 - and destination telephony devices 8 is perceived to be direct. Phone calls made by the call bridge 4 can be via circuit switched network (e.g. the Public Switched Telephone Network (PSTN)) or can be via the lntemet 10 (e.g. using Voice over internet Protocol (VoIP) technology) or a combination of these and other technologies. The structure and operation of the Internet and the use of communication protocols such as Internet Protocol^'(IP) and VoIP is well known and need not be further described.

For the purposes of lowering the cost of establishing and maintaining call legs 6, 7, it is preferable to use the Internet and VoIP technology where possible. Ideally, there will one or more call bridges 4 located in each country. Each call bridge 4 will be identified with a unique identifier CS/ and be callable via a set of Ki (where Kj is an integer greater than zero) telephone numbers Λ/CS/,_fc (k = 1,2, ... Ki), for example through the use of Direct Inward Dialling (DID) numbers.

In order to couple PSTN calls to VoIP (and vice versa) media gateways 3 are used - as illustrated in the Figures.

The way in which a roaming mobile phone 5 is able to establish a call to a remote telephony device 8, such a fixed landline phone, or a mobile phone, located in another country, using the communications system of the present invention will now be described.

It is assumed that the user of the roaming mobile phone 5 has enabled international roaming and has access to a local mobile telephone network 9. The structure and operation of mobile phones and cellular telephone networks is well known to persons skilled in the art and need not be described in any further detail herein.

It is also assumed that user of the roaming mobile phone 5 has pre-installed the mobile phone software application. When the mobile phone software application is running, the roaming mobile phone 5 is operable, under control of the software application to send a short packet of data to the call server 2 - via GPRS or other method as described above -to indicate that roaming mobile phone 5 is located within a specific area. In this way, the call server 2 is able to determine where the roaming mobile phone 5 is located. In a first embodiment of the invention, one method for making a call between an initiating roaming mobile phone 5 to a destination telephony device 8 located in another country is as follows, and as illustrated in Figures 2 and 3:

1 ) The user at the roaming mobile phone 5 uses the pre-installed mobile phone software application to place a call to the required destination telephony device 8.

2) The mobile phone software application will send a short message to the call server 2 via GPRS 11 (or otherwise) with the call details, including;

a. the source roaming mobile phone 5 phone number, N_ε, and possibly other identifiers that uniquely identify the roaming mobile phone 5, and

b. destination telephony device 8 phone number, N_d.

At the call server 2:

Upon receiving the call request from the roaming mobile phone 5, the call server 2 will nominate a suitable call bridge having the identifier CSy that is callable via at least one telephone number NCB_j._k. Preferably, this number will be one that will incur a small or minimal call cost when the roaming mobile phone 5 establishes communication with nominated call bridge CBj via this number. The call server 2 will proceed according to the following pseudo code:

IF CALLJ³ROCEEDINGy = IDLE THEN

i. Set QALL-PROCEEDINGy₁Jt = IN_PROGRESS

ii. Signal nominated call bridge CB₁ and transmit the phone number N_s of the roaming mobile phone 5 (and possibly other identifiers that uniquely identify the roaming mobile device), the destination number N_d of the destination telephone device

8, the nominated call bridge number NCB_j,_k, together with a uniquely generated CALLJD and the TONEJD identifying this call to nominated call bridge CB_j.

iii. In response to this, and with one or more messages, the call server 2 will then transmit the following data to the initiating roaming mobile phone 5 software application

a) a telephone number NCB_jx of nominated call bridge CBf₁ and

b) the TONEJD associated with this call,

iv. Upon call response status from CS₇- or timeout

IF CB_j responds with SUCCESS for this CALLJD THEN

Start call detail record for this call. Call detail records are used for user accounting and billing.

ENDIF

Set CALLJ³ROCEEDINGy,* = IDLE

ELSE

Wait (with timeout) for CALL.PROCEEDING^ = IDLE

ENDIF

At the initiating, source, roaming mobile phone.5:

Upon receiving the telephone number /VCSy,* of nominated call bridge CB_j and the TONEJD associated with the call from the call server 2, the mobile phone software application will initiate a call to nominated call bridge CSy using the telephone number NCBJX When nominated call bridge CB₁ answers, the mobile phone software application immediately sends, in order, the sequence of DTMF tones contained in the signalled TONEJD.

At nominated call bridge CB/.

Upon receiving the call request from the call server 2, nominated call bridge CBj then establishes the two call legs - a first call leg 6 and second call leg 7 of Figure 2 - that will constitute the call between the roaming mobile phone 5 and the required destination telephony device 8 in the following manner:

Set CONFIRM = FALSE

Wait (with a timeout) for next incoming call on the telephone number NCB^

JF next call on the telephone number NCB^ has caller ID (CID) information present THEN

IF CID = Ns (or other unique identifier for the mobile roaming phone 5) CONFIRM = TRUE

ENDIF

ELSE

CONFIRM = TENTATIVE

ENDIF

IF CONFIRM = FALSE THEN return FAILED status associated with this CALLJD to the call server 2 and exit.

IF CONFIRM = TRUE OR CONFIRM = TENTATIVE THEN

Make a call to the telephone number N_d of the destination, telephony device 8 IF call with N₀ is NOT RINGING THEN

Alert BUSY or otherwise detected state to roaming mobile phone 5

Return FAILED status associated with this CALLJD to call server 2 and exit

ENDIF ;

ELSE IF call with destination telephony device 8 N_d is RINGING

THEN

Alert the roaming mobile phone 5 with RINGING

Wait for answer at the telephone destination device A/

If the destination telephony device 8 answers (and thereby establishing the second call leg 7) THEN

Answer roaming mobile phone 5 ^and thereby establishing first call leg 6)

Record transmitted tones by the mobile phone into Tonejd

IF Tonejd = TONEJD associated with this CALLJD THEN

Bridge the first and second call legs 6, 7 (such that the source roaming mobile phone 5 and destination telephony device 8 perceive the call to be direct).

CONFIRM = TRUE

Return SUCCESS status associated with this CALLJD to the call server 2

ELSE (wrong tone ID or no tones detected)

Terminate two call legs Return FAILED status associated with this CALL_ID to the call server 2 and exit

ENDlF

Upon the event that either source roaming mobile phone 5 or the destination telephony device 8 terminates the call or the call attempt process is terminated for any reason, then the call bridge CB_j is operable to return TERMINATE status associated with the CALLJD of the terminated call to the call server 2.

At the call server 2, and upon receiving the TERMINATE status from nominated call bridge CS/ for that CALLJD, the call server 2 records the call detail record for that call if it was initially successful in setting it up.

In a second embodiment of the invention, a method for making a call from a telephone device 12 in one country to a roaming mobile phone 5 located in another country will now be described with reference to Figures 4 and 5.

As above, it is assumed that the user of the roaming mobile phone 5 has enabled international roaming. It is also assumed that user of the roaming mobile phone 5 has pre-installed the mobile phone software application. As before, the roaming mobile phone 5, under control of the software application, is operable to transmit a data packet to the call server 2 indicating Its location via a communications link 11 such as GPRS or any other suitable method as described in respect of the first embodiment,

In addition, the user of the roaming mobile phone 5 will have set up a 'call divert' function to divert incoming calls to the roaming mobile phone 5 number to a suitable telephone number, NCB_h,_p, designated for a call bridge denoted as the home call bridge 4" and having an identifier CBu- Thus, any phone call made to the roaming mobile phone 5 will be diverted - in the usual, known manner -to home call bridge CB_h-

One method for making a call from a source telephony device 12 to the roaming mobile phone 5 is as follows, and is illustrated in Figure 4: 1. The source telephony device 12 makes a call to the roaming mobile phone 5 and the call is diverted to home cai! bridge CB_f, in the usual way, for example via a PSTN network 9 and media gateway 3. This is a second call leg 14.

2. From the caller ID information contained in call setup message from the source telephony device 12 (or otherwise), home call bridge CB_h is operable to extract the phone number N_s of the source telephony device 12, and the phone number /V^ destination roaming mobile phone 5 being called.

3. Home call bridge CBi₁ then establishes the "ringing" alert tone for source initiating telephony device 12.

4. Home call bridge CS_/, is then operable to transmit - to the call server 2 - the phone number N₃ of both the source telephony device 12, and the phone number of the roaming mobile phone 5 N^, as well as a CALLJD which uniquely identifies this call, the CALLJD being created by home call bridge CB/, in response to this call request.

5. The call server 2 is then operable to nominate a suitable call bridge having the identifier CS/ which preferably will be callable using a number, WCBy_1R that will incur a small or minimal call cost when the destination roaming mobile phone 5 establishes a call with nominated call bridge CBj having this number (on the basis of the information sent from the roaming mobile phone 5 regarding its location) and to transmit this data to home call bridge CB_h so that home call bridge CBh can communicate with nominated call bridge CB_j. Home call bridge CB_h and nominated call bridge CB_j can be the same call bridge devices if they are both callable with suitable phone numbers.

6. Upon receiving information about nominated call bridge CSy, home call bridge CB_h is operable to establish a call between itself and nominated call bridge CBj associating it with the CALLJD. This inter- call bridge call leg 13 between the two call bridges CBn, CBj and is only necessary where the two bridges are not the same. If the inter-call bridge call leg 13 is required, then it can be established over the Internet 10 using VoIP, or the call can be established by any other suitable communications means.

The system 1 then proceeds as follows:

At the call server 2:

The call server 2 proceeds according to the following pseudo code:

IF CAUL-PROCEEDING^ = IDLE THEN

i. Transmit the roaming mobile phone 5 number Λ/_Λ the nominated call bridge number NCB^, together with the unique CALLJlD and a randomly generated TONEJD identifying the call to nominated call bridge CSy. This CALLJD is Identical to the CALLJD that home call bridge CB_h used to establish a call connection between itself and nominated call bridge CB₁

ii. With one or more messages, the call server 2 then signals to the roaming mobile phone 5 software application:

a) the telephone number NCB₁^ of CBj; and

b) the TONEJD associated with this call,

iii. Set CALL-PROCEEDINGy₁* = IN_PROGRESS

iv. Upon call response status from nominated call bridge CS/ or timeout

IF nominated call bridge CB₁ responds with SUCCESS for this CALLJD THEN

Start call detail record for this call ENDIF

Set CALL_PROCEEDING_;,_fr = IDLE

ELSE

Wait (with timeout) for CALL-PROCEEDING^ = IDLE

ENDIF

At the called roaming mobile phone 5 :

Upon receiving the telephone number Λ/CSy^of nominated call bridge CSy and the TONE_ID associated with this call from the call server 2 the roaming mobile phone 5 , under control of the mobile phone software application, will initiate a call to nominated call bridge CB_j using the number NCB_jιk_ When nominated call bridge CBj answers, then the roaming mobile phone 5, under control of the software application, immediately sends, in order, the sequence of DTMF tones contained in the signalled TONEJD. In this way, a first call leg 15 is established between the roaming mobile phone 5 and nominated call bridge CB_j.

At nominated call bridge CBf

Upon receiving the call request from the call server 2, nominated call bridge CB_j is then operable to then establish a call between the roaming mobile phone 5 and home call bridge CB_h in the following manner:

Set CONFIRM = FALSE

Wait (with a timeout) for next incoming call on the telephone number NCB^

IF next call on the telephone number NCBj^ has caller ID (CID) information present THEN IF CID = N_s (or other unique identifier for the mobile roaming phone 5)

CONFIRM = TRUE

ENDIF

ELSE

CONFIRM = TENTATIVE

ENDIF

IF CONFIRM = FALSE THEN return FAILED status associated with this CALLJD to the call server 2 and exit

IF CONFIRM = TRUE OR CONFIRM = TENTATIVE THEN

Answer the roaming mobile phone 5

Record transmitted tones by the roaming mobile phone 5 into Tone_id

IF Tone_id = TONEJD associated with this CALLJD THEN

Bridge the call between roaming mobile phone 5 and home call bridge CB_f1, and notify home call bridge CS/, of successful call bridging

Return SUCCESS status associated with this CALLJD to the call server 2

ELSE (wrong tone ID or no tones detected)

Terminate the two call legs

Return FAILED status associated with this CALL ID to the call server 2 and exit ENDIF

ENDIF

At home call bridge CBw.

Upon successful call bridging at nominated call bridge CSy, home call bridge CB_f1 answers the call to source telephony device 12 and then bridges the call to nominated call bridge CB_j. The roaming mobile phone 5 and source telephony device 12 perceive the call to be direct at this time.

Upon the event that either roaming mobile phone 5 or the source telephony device 12 terminates the call or the call attempt process is terminated for any reason, then nominated call bridge CSy or home call bridge CB_f7 returns

TERMINATE status associated with the CALLJD of the terminated call to call server 2.

At the call server 2:

Upon receiving a FAILED status from nominated call bridge CBj, the call server 2 is operable to transmit a FAILED status to home call bridge CB_h. Home call bridge CB_h is then either operable to terminate the call OR prompt the originating caller to leave a voice mail message.

Upon receiving the TERMINATE status from nominated call bridge CSy or from home call bridge CB_h, the call server 2 completes the call detail record for the call associated with CALLJD if it was initially successful in setting it up.

It should be noted, that where there is only one call bridge i.e. two call bridges CB_h, CB_j are the same then certain steps as describe with regard to Figure 5 can be illustrated different. In this case, the step A of Figure 5 is not required. Similarly, the mobile phone 5 will call the home call bridge 4" (step B of Figure 5), step C of Figure 5 will not be required, and the billing (step D of Figure 5) will take place between the home call bridge 4" and the call server 2. In a third embodiment of the invention, there is a method for recording a voice mail message (or other media message, e.g. picture, video, multi-media, etc.) and then retrieving the voice mail message from a roaming mobile phone 5. This will now be described with reference to Figure 6 and Figure 4, with particular reference to a voice mail message being used. However, as stated, other media messages may be used in this embodiment.

As described above, it is assumed that the user of the roaming mobile phone 5 has enabled international roaming. It is also assumed that user of the roaming mobile has pre-installed the mobile phone software application, and that the software application is running. As before, the roaming mobile phone 5, under control of the software application, is operable to transmit a data packet to the call server 2 indicating its location via a communications link 11 such as GPRS or any other suitable means as in the previous embodiments.

In addition, the user of the roaming mobile phone 5 will have set up a 'call divert' function to divert incoming calls to the roaming mobile phone 5 number to a suitable telephone number, NCB^p, designated for a home call bridge 4" located in the roaming mobile phone 5 's country of origin and having the identifier CB/,. Thus, any phone call made to the roaming mobile phone 5 will be diverted - in the usual, known manner -to home call bridge CBh-

One method for recording a voice mail message and then retrieving that voice mail message by a roaming mobile device is as follows:

1 ) An initiating source telephony device 12 makes a call to the roaming mobile phone 5 and the call is diverted to the home call bridge 4" having the identifier CS_/,.

2) From the caller ID information contained in call setup message from the source telephony device 12 (or otherwise), home call bridge CSj, extracts the phone number N₃ of the source telephony device 12, and the number N_d of the destination roaming mobile phone 5 being called. 3) Home call bridge CB_h is then operable to establish a "ringing" alert tone for source telephony device 12.

4) Home call bridge CB_h is then operable to transmit both the source telephony device number N_s, and number /V^ of the roaming mobile phone 5 and a generated CALLJD which uniquely identifies this call, to the call server 2.

5) The call server 2 will nominate a suitable call bridge 4' having the identifier CB_j that preferably will be callable with a number, NCBj_1K that will incur a small or minimal call cost when the destination roaming mobile phone 5 establishes a call with this number. Details of this nominated call bridge

CB_j is then transmitted back home call bridge CS_f, by the call server 2. In an alternative embodiment, the two call bridges CS_/,, CB,- can be the same call bridge device, e.g. if they are both callable with suitable phone numbers. In the case that the two call bridges CB_h and CBj are the same call bridge device, that call bridge device contains the functionality that is described herein in relation to both the call bridges CS/, and CBj. In Figure 6, the use of a single such call bridge device is represented by the home call bridge 4"; in such a case, the nominated call bridge for 4' is omitted. This embodiment will be described further later herein.

6) Upon receiving the nominated call bridge CBj data, home call bridge CB_n answers the call from the source telephony device 12 and is then operable to transmit a message to the initiating source telephony device prompting the caller to "leave a message". The caller will then leave a message in response to the prompts in the usual, known manner. This voice message from the caller is stored on the hard disk at home call bridge CB_Λ in any suitable audio format as a file.

7) Once the caller has completed leaving the voice message, then home call bridge CB_h signals the call server 2 indicating that a voice message for this CALLJD is ready for retrieval. 8) Home call bridge CB_h is then operable to forward the data file (via the Internet 10 or other suitable means) containing the voice mail message to nominated call bridge CB_j together with the CALLJD associated with this call message. This inter-call bridge file transfer between the {wo call bridges CS_/,, CB_j is only required in the embodiment in which the two bridges are not the same device.

At the call server 2:

Upon receiving the voice mail ready message from home call bridge CB_h, the call server 2 proceeds according to the following pseudo code:

IF CALL-PROCEEDING^ = IDLE THEN

i. Signal nominated call bridge CBj and transmit the nominated call bridge number NCBj._k, the number N_<j of roaming mobile phone 5 together with the unique CALLJD and a randomly generated TONEJD identifying this call. This CALLJD is identical to the CALLJD that home call bridge CB_h used to establish a call connection between itself and nominated call bridge

CB_j.

ii. With one or more messages, signal the roaming mobile phone 5 (which has the telephone number Nd.) indicating a message is ready for retrieval . and transmit the following data to that mobile phone software application:

i. a telephone number NCB^ of nominated call bridge CB_j; and

ii. the TONEJD associated with this call.

iii. Set CALL_PROCEEDING/,* = IN_PROGRESS

iv. Upon call response status from nominated call bridge CB_j or timeout

IF nominated call bridge CBj responds with SUCCESS for this CALLJD THEN Start call detail record for this voice mail retrieval service

ENDIF

Set CALLJ³ROCEEDING^ = IDLE

ELSE

Wait (with timeout) for CALL_PROCEEDING^ = IDLE

ENDIF

At the called roaming mobile phone 5 :

Upon receiving the telephone number

nominated call bridge CS/ and the TONEJD associated with this call from the call server 2, the roaming mobile phone 5 , under control of the mobile phone software application, initiates a call to nominated call bridge CBj using the number NCBjx When nominated call bridge CBj answers, then the roaming mobile phone 5, under control of the mobile phone software application, immediately sends, in order, the sequence of DTMF tones contained in the signalled TONEJD.

At nominated call bridge CBf.

Upon receiving the voice mail retrieval request from the call server 2, nominated call bridge CB_j is then operable to establish a call between the roaming mobile phone 5 and nominated call bridge CB_j in the following manner

Wait (with timeout) for next incoming call

Set CONFIRM = FALSE

Wait (with a timeout) for next Incoming call on the telephone number NCBj_1K IF next call on the telephone number

has caller ID (CID) information present THEN

IF CID = N₃ (or other unique identifier for the mobile roaming phone 5)

CONF1RM = TRUE

ENDIF

ELSE

CONFIRM = TENTATIVE

ENDIF

IF CONFIRM = TRUE OR CONFIRM = TENTATIVE THEN

Answer the roaming mobile phone 5

Record transmitted tones by the roaming mobile phone 5 into Tonejd

IF Tonejd = TONEJD associated with this CALLJD THEN

Play back the voice mail message to the roaming mobile phone 5 (the voice mail message being stored at nominated call bridge CBj).

Return SUCCESS status associated with this CALLJD to call server 2

ELSE

Return FAILED status associated with this CALL ID to call server 2 and exit ENDIF

ENDlF

Upon completion of the play back of the voice mail message, nominated call bridge CS/ returns TERMINATE status associated with the CALLJD of the terminated call to the call server 2.

At the call server 2:

Upon receiving the TERMINATE status from nominated call bridge Cβ/the call server 2 completes the call detail record for the call associated with CALLJD if it was initially successful in setting it up.

In another, fourth, embodiment of the invention, the system described above in relation to Figure 7, can be used to facilitate communication between a cellular radio telephone and a telephony device, whether or not the cellular radio telephone is 'roaming', and, as such, they need not be in different countries.

In this embodiment, therefore, the mobile phone 5 does not need to be roaming. In this embodiment, the mobile phone 5 may be in a network where, for the service that the mobile phone is subscribed to, call tariffs to certain destinations may be lower than for calls to certain other crestinations.

It is assumed that user of the mobile phone 5 has pre-installed the mobile phone software application as described above in respect of the other embodiments.

The method for making a call from the mobile phone 5 to the destination telephony device 8 is as follows, and is described with reference to Figure 7:

1) The user at the mobile phone 5 uses the pre-installed mobile phone software application to place a call to the required destination telephony device 8. 2) The mobile phone software application will send a short message as a call request to the call server 2 via a communications link 11 such GPRS (or otherwise) with the call details, including;

a. the number N₅ of mobile phone 5 , and possibly other identifiers that uniquely identify the mobile phone 5, and

b. the phone number, Nd. of the destination telephony device 8.

At the call server 2:

Upon receiving the call request from the mobile phone 5, the call server 2 will nominate a suitable or optimum call bridge 4 having an identifier CB_j . The basis on which nominated call bridge CB₁ is chosen can for example be based on the knowledge that the tariff for the mobile phone 5 to call a certain call bridge callable with a telephone number NCBj_tK is lower than the default or usual tariff io call the number, Nd of the destination telephony device 8. Additionally, the geographical location of a call bridge 4 can determine delay characteristics associated with the final end to end call and can also be considered in order to minimise call delay characteristics. Once a suitable nominated call bridge CB_j is chosen the call server 2 proceeds according to the following pseudo code:

IF CALL_PROCEEDING_A* s IDLE THEN

i. Set CALL_PROCEEDING/,* = IN_PROGRESS

ii. Signal nominated call bridge CSy and transmit the mobile phone number N_s (and possibly other Identifiers that uniquely identify the mobile phone 5) of the mobile phone 5 the telephone number NCB_j^ and the number N_d of the destination telephony device 8, together with a uniquely generated CALLJD and TONEJD identifying this call. iii. In response to this, and with one or more messages, the call server 2 will then transmit data to the initiating mobile phone 5 software application

a. a telephone number Λ/CB/,_kof nominated call bridge CB₁

b. the TONEJD associated with this call.

iv. Upon call response status from nominated call bridge CBj or timeout .

IF nominated call bridge CB₁ responds with SUCCESS for this CALLJD THEN

ENDIF

Set CALLJ³ROCEEDINGy,* = IDLE

ELSE

Wait (with timeout) for CALLJ³ROCEEDING/,* = IDLE

ENDIF

At the initiating mobile phone 5:

Upon receiving the telephone number NCB_j^of nominated call bridge CBj and the TONEJD associated with this call from the call server 2, the mobile phone software application will initiate a call to nominated call bridge CS/ using the number NCBj_1K. When nominated call bridge CBj answers, the mobile phone software application immediately sends, in order, the sequence of DTMF tones contained in the signalled TONEJD. At nominated call bridge CBf.

Upon receiving the call request from the call server 2, nominated call bridge CS; then establishes two call legs - a first call leg 6 and a second call leg 7 - that will constitute the call between the mobile phone 5 and the required destination telephony device 8 in the following manner:

Set CONFIRM = FALSE

Wait (with a timeout) for next incoming call on the telephone number NCB₁^

IF next call on the telephone number NCB^has caller ID (ClD) information present THEN

IF ClD = N_s (or other unique identifier for the mobile phone 5)

CONFIRM = TRUE

ENDIF

ELSE

CONFIRM = TENTATIVE

ENDIF

IF CONFIRM = FALSE THEN return FAILED status associated with this CALLJD to the call server 2 and exit. ^•

IF CONFIRM = TRUE OR CONFIRM = TENTATIVE THEN

Make a call to the telephone number N_d of the destination telephony device 8

IF call with N_d is NOT RINGING THEN Alert BUSY or otherwise detected state to mobile phone

Return FAILED status associated with this CALLJD to call server 2 and exit

ENDIF

ELSE IF call with destination telephony device 8 is RINGING THEN

Alert the mobile phone 5 with RINGING

Wait for answer at the telephone destination device 8

Answer mobile phone 5 (and thereby establishing first call leg 6)

Record transmitted tones by the mobile phone into Tone_id

IF Toπejd = TONEJD associated with this CALLJD THEN

Bridge the first call leg 6 and the second call leg 7 (such that the source mobile phone 5 and destination telephony device 8 perceive the call to be direct).

CONFIRM = TRUE

Return SUCCESS status associated with this CALLJD to the call server.2

ELSE (wrong tone ID or no tones detected)

Terminate two call legs

Return FAILED status associated with this CALLJD to the call server 2 and exit

ENDIF Upon the event that either source mobile phone 5 or the destination telephony device 8 terminates the call or the call attempt process is terminated for any reason, then nominated call bridge CB_j is operable to return TERMINATE status . associated with the CALLJD of the terminated call to call server 2.

At the call server 2, and upon receiving the TERMINATE status from nominated call bridge CB_j for that CALLJD, the call server 2 records the call detail record for that call if it was initially successful in setting it up.

The preceding description of an embodiment of a method for recording a voice mail message and then retrieving that voice mail message by a roaming mobile device 5 also introduced an alternative embodiment where the two call bridges CB_h and CSy can be the same call bridge device. In such an embodiment, the functionality of the call bridges CS_/, and CB₁ are incorporated in a single call bridge. This alternative embodiment has been denoted in Figure 6, in which call bridge 4" may be used as the single call bridge. In such an embodiment, the step W of sending a voice message file to the nominated call bridge 4' does not occur, since there is no nominated call bridge 4'. Instead, the steps that occur are shown by the extra broken lines X, Y and Z in Figure 6. The broken line X shows that the mobile phone 5 calls the call bridge 4"; the call bridge 4" plays back the voice mail message to the mobile 5; and the return call detail records for billing come from the call bridge A".

In another, fifth, embodiment of the invention, the system 1 described in respect of Figure .4 can be used to establish communication between a mobile phone 5 whether it is in a roaming environment or elsewhere - for example to enable another, more cost effective, call tariff to be used where a remote, initiating telephony device 12 is used to call the mobile phone 5. The system 1 is as illustrated in Figure 4 (except that the reference to the mobile phone 5 can be any mobile phone, not just a roaming phone).

Again, it is assumed that user of the mobile phone 5 has pre-installed the mobile phone software application. In addition, the user of the mobile phone 5 will have set up a 'call divert' function to divert incoming calls to the number of the mobile phone to the telephone number designated for a call bridge 4" located in the phone's country of origin and denoted as a home call bridge 4" having an identifier CBn).

The method for making a call between an initiating telephony device 12 to the mobile phone 5 is as follows with reference to Figure 8:

1. The initiating telephony device 12 makes a call to the mobile phone 5 and the call is diverted to home call bridge CB_t1.

2. From the caller ID information contained in call setup message from the initiating telephony device 12 (or otherwise), home call bridge CB_h extracts the phone number N_s of the initiating telephony device 12, and the number

N_d of the mobile phone 5 being called.

3. Home call bridge CB_h establishes the "ringing" alert tone for initiating telephony device 12.

4. Home call bridge CB_h transmits the initiating telephony device number N₈, and the mobile phone number Nj and a CALLJD which uniquely identifies

^' this call to the call server 2.

5. The call server 2 is then operable to nominate a suitable call bridge 4' with an identifier CBj₁ with which the mobile phone 5 should communicate. The basis on which nominated call bridge CSy is selected can for example be based on the knowledge that the tariff for the mobile phone 5 to call nominated call bridge CS/ (callable with a telephone number NCBj,_k), is lower than the tariff to receive a call from the initiating telephony device 12 using the usual, default network or rates. Additionally, the geographical location of nominated call bridge CB_j can determine delay characteristics associated with the final end to end call and can also be considered in order to minimise call delay characteristics. Details of nominated call bridge CSy are the transmitted back to home call bridge CS_/,, so that home call bridge CB_f1, can communicate with nominated call bridge CBj, The rest of the process is the same as described above with reference to Figures 4 and 5.

In another, sixth, embodiment of the invention, there is a system described in respect of Figure 9 that can be used to record and retrieve a recorded voicemail message for a mobile phone 5 whether it is in a roaming environment or elsewhere - for example to enable another, more cost effective, call tariff to be used where a remote, initiating telephony device 12 is used to call the mobile phone 5. The system 1 is as illustrated in Figure 9.

As described in previous embodiments, ft is assumed that user of the mobile phone 5 has pre-installed the mobile phone software application. Further it is assumed that the 'call divert' function has been enabled, where calls are diverted to a home call bridge 4" with the identifier CS/,.

The method for recording a voice mail message and then and retrieving that voice mail message from mobile phone 5 is as follows with reference to Figure 9:

1 ) An initiating source telephony device 16 makes a call to the mobile phone 5 and the call is diverted in the usual way to home call bridge CB_h .

2) From the caller ID information contained in call setup message from the source telephony device 16 (or otherwise), home call bridge CS/, is operable to extract the phone number N_s of the initiating source telephony device 16, and the phone number N^ of the destination mobile phone 5.

3) Home call bridge CB_h then establishes the "ringing" alert tone for initiating source telephony device N_s.

4) Home call bridge CB_h transmits both the initiating source telephony device phone number N_s, and the mobile phone number N_d and a CALLJD which uniquely identifies ihis call to the call server 2. 5) The call server 2 is then operable to nominate a call bridge 4' with the Identifier CB₁, with which the mobile phone 5 is to communicate. The basis on which nominated call bridge CS/ is chosen can for example be based on the knowledge that the tariff for the mobile phone 5 to used to/etrieve the voice mail message from nominated call bridge CSy(wlth a telephone number /VCβ/,κ), is lower than the usual, default tariff used to receive a voicemail message from an alternative voice mail recording device. Details of nominated call bridge CBj is the transmitted back to home call bridge CB_h.

The system then proceeds to operate in the same way as described above in respect of the embodiment described with reference to Figure 6.

Various modifications and alternatives are possible within the scope of the present invention. For example and as referred to above, different numbers of call bridges can be used. Although only one call server 2 is described in this embodiment, several could equally be used. As well as VoIP, other suitable communications protocols can also be used. The mobile phone application can use other suitable ^"programming languages and in particular, other languages for scripting user interfaces, The call server 2 can be used to store any suitable information that may be required by the system of the invention.

It is envisaged that more than one call bridge 4 could be utilised for calls from the mobile phone 5 to the telephony device 8, although the use of a single call bridge 4 is probably preferable.

Claims

Claitns

1. A method of establishing communication in a communication system using at least one telephony device and at least one communications interface characterised in that it comprises

. receiving and communicating call data to the at least one communications interface about a call initiated by a telephony device,

establishing communication between a communications facilitator and a first telephony device to identify said at least one communications interface to said first telephony device, and

establishing at least a first call leg between said first telephony device and said at least one communications interface to allow access to communications data routed via said at least one communications interface.

2. A method according to claim 1 , wherein the call initiated by a telephony device is initiated by said first telephony device.

3. A method acqording to any one of the preceding claims, wherein receiving cail data comprises receiving call data at said communications facilitator transmitted from said first telephony device, said call data comprising a request for establishment of communication with a second telephony device.

4. A method according to any one of the preceding claims, wherein communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data ^' from said communications facilitator to the at least one communications interface about a call initiated by said first telephony device.

5. A method according to any one of the preceding claims, further comprising: signalling said first telephony device to call said at least one communications interface to establish communication between said first telephony device and said at least one communications interface thereby establishing said first call leg.

6. A method according to any one of the preceding claims, further comprising establishing communication between the at least one communications interface and a second telephony device to establish a second call leg; and coupling the first call leg and the second call leg at the at least one communications interface to thereby establish communication between said first telephony device and said second telephony device.

7. A method according to any one of the preceding claims, wherein said communications data routed by said communications interface comprises call data from said second'telephony device. 8. A method according to claim 1, wherein the call initiated by a telephony device is initiated by a second telephony device.

9. A method according to claim 8 wherein the receiving call data comprises receiving call data at the at least one communications interface transmitted from the second telephony device, said call data comprising a request for the establishment of communication with the first telephony device.

10. A method according to claim 8 or claim 9, wherein the communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data to the at least one communications interface about a call initiated by the second telephony device.

11.A method according to any one of claims 8 to 10, further comprising signalling said first telephony device tα call said at least one communications interface to establish communication between said first telephony device and said at least one communications interface thereby establishing said first call leg. 12.A method according to any one of claims 8 to 11 , comprising establishing communication between the communication facilitator and the at least one communications interface to transmit the call data to the communications facilitator from the at least one communications interface.

13. A method according to any one of claims 8 to 12, comprising identifying the at least one communications interface on the basis of the transmitted data received by the communications facilitator from the at least one communications interface.

14. A method according to any one of claims 8 to 13, the method comprising:

establishing a second call leg between the second telephony device and the at least one communications interface; and

coupling the first and second call legs at the at least one communications interface to thereby establish communication between the first telephony device and the second telephony device.

15. A method according to any one of claims 8 to 14, wherein said communications data routed by said communications interface comprises call data from said second telephony device.

16. A method according to any one of claims 8 to 15, wherein the wherein the system includes a first communications interface and a second communications interface, and the call initiated by a telephony device is routed via the first and second communications interfaces, and wherein the first call leg is established between the first telephony device and the first communications interface, the method comprising:

coupling the first communications interface and the second communications interface to establish data communication therebetween; establishiπg a third call leg between the second telephony device and the second communications interface; and

17.A method according to claim 16, whereby the coupling of the first communications interface and the second communications interface is enabled by:

establishing communication between the first communications interface and the second communications interface upon receipt by the second communications interface of the identity of the first communications interface.

1β. A method according to claim 16 or claim 17, wherein the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral within said single unit.

19.A method according to claim 16 or claim 17, wherein the first communications interface and the second communications interface are provided remote from each other, and the method comprising:

establishing a fourth call leg between the first communications interface and the second communications interface prior to establishing the third call leg to couple the first communications interface and the second communications interface; bridging the first call leg and the fourth call leg at the first communications interface; and

20. A method according to claim 1, wherein the call initiated by a telephony device is initiated by a second telephony device.

21. A method according to claim 21 , wherein receiving and communicating call data to the at least one communications interface about a call initiated by a telephony device comprises receiving call data from the second telephony device about the call initiated by the second telephony device and communicating the call data to the at least one communications interface about the call initiated by the second telephony device.

22.A method according to claim 20 or claim 21 , comprising establishing communication between the communication facilitator and the at least one communications interface to transmit the call data to the communications facilitator from the at least one communications interface.

23.A method according to any one of claims 20 to 22, comprising identifying the at least one communications interface on the basis of the transmitted call data received by the communications facilitator from the at least one communications interface. 24.A method according to any one of claims 20 to 23, wherein said method further comprises storing audio or other multimedia information received from said second telephony device at said at least one communications interface, said audio or multimedia forming said communications data routed by said at least one communications interface..

25. A method according to claim 24, further comprising transmitting notification from said at least one communications interface to said communications facilitator of the storage of said audio or multimedia information.

26. A method according to claim 24 or claim 25, further comprising

27.A method according to any one of claims 24 to 26, wherein it further comprises receiving a request at said at least one communications interface from said first telephony device for retrieval of said audio or multimedia information.

28.A method according to any one of claims 24 to 27, wherein it further comprises transmitting said stored audio or multimedia information from said at least one communications interface to said first telephony device.

29.A method according to any one of claims 24 to 28, wherein the system

Includes a first communications interface and a second communications interface, and the call data relating to the call initiated by the second telephony device is communicated to the first communications interface, the method further comprising:

transmitting said stored audio or multimedia information from said first communications interface to said second communications interface.

30. A method according to claim 29, further comprising transmitting notification from said first communications interface to said second communications interface of the storage of said audio or multimedia information.

31. A method according to claim 29 or claim 30, whereby the coupling of the first communications interface and the second communications interface is enabled by:

establishing communication between the first communications interface and the second communications interface upon receipt by the. first communications interface of the identity of the second communications interface.

32.A method according to any one of claims 29 to 31, further comprising:

33.A method according to any one of claims 29 to 32, wherein it further comprises receiving a request at said second communications interface from said first telephony device for retrieval of said audio or multimedia information.

34.A method of according to any one of claims 29 to 33, wherein it further comprises transmitting said stored audio or multimedia information from said second communications interface to said first telephony device.

35.A method according to any one of claims 29 to 34, wherein the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral within said single unit.

36.A method according to any one of claims 29 to 35, wherein the first communications interface and the second communications interface are provided remote from each other.

37.A communication system including at least one telephony device, at least one communications interface and a communications facilitator, wherein the at least one communications interface and the communications facilitator are arranged to communicate, said communications facilitator being operable to receive call data about a call initiated by a telephony device, and the communications facilitator being operable to communicate with a first telephony device to identify the at least one communications interface to said first telephony device, and

38.A communication system according to claim 37, wherein the call initiated by a telephony device is initiated by said first telephony device.

39.A communication system according to claim 37 or claim 38, wherein receiving call data comprises receiving call data at said communications facilitator transmitted from said first telephony device, said call data comprising a request for establishment of communication with a second telephony device.

40. A communication system according to any one of claims 37 to 39, wherein communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data from said communications facilitator to the at least one communications interface about a call initiated by said first telephony device.

41. A communication system according to any one of claims 37 to 40, wherein the communications facilitator is operable to signal said first telephony device to call said at least one communications interface to establish communication between said first telephony device and said at least one communications interface thereby establishing said first call leg.

42.A communication system according to any one of claims 37 to 41, wherein the communications interface is operable to establish communication between the at least one communications interface and a second telephony device to establish a second call leg, and to couple the first call leg and the second call leg at the at least one communications interface to thereby establish communication between said first telephony device and said second telephony device.

43. A communication system according to any one of claims 37 to 42, wherein said communications data routed by said communications interface comprises call data from said second telephony device.

44.A communication system according to claim 37, wherein the call initiated by a telephony device is initiated by a second telephony device.

45.A communication system according to claim 44, wherein the receiving call data comprises receiving call data at the at least one communications interface transmitted from the second telephony device, said call data comprising a request for the establishment of communication with the first telephony device.

46. A communication system according to claim 44 or claim 45, wherein the communicating call data to the at least one communications interface about a call initiated by a telephony device comprises communicating call data to the at least one communications interface about a call initiated by the second telephony device.

47. A communication system according to any one of claims 44 to 46, wherein the communications facilitator is operable to establish communication between the communication facilitator and the at least one communications interface to transmit the call data to the communications facilitator from the at least one communications Interface.

48.A communication system according to any one of claims 44 to 47, wherein the at least one communications interface is identified on the basis of the transmitted data received by the communications facilitator from the at least one communications interface.

49.A communication system according to any one of claims 44 to 48, wherein the communications interface is operable to establish communication between the second telephony device and the at least one communications interface to establish a second call leg; and to couple the first and second call legs at the at least one communications interface to thereby establish communication between the first telephony device and the second telephony device.

50. A communication system according to any one of claims 44 to 49, wherein said communications data routed by said communications interface comprises call data from said second telephony device.

51. A communication system according to claim 50, wherein the system includes a first and a second communications interface, and the call initiated by a telephony device is routed via the first and second communications interfaces and wherein the first call leg is established between the first telephony device and the first communications interface, and the first communications interface is arranged for coupling with the second communications interface, and the second communications interface is operable to establish a third communication leg with the second telephony device and the second Communications interface such that coupling of the first and third legs via said first communications interface and said second communications interface thereby establishes communication between the first telephony device and the second telephony device.

52.A communication system according to claim 51 , wherein the communications facilitator is in data communication with the second communications interface and Is operable to communicate the identity of the first communications interface to the second communications interface such that the first communications facilitator is arranged to communicate with the first communications facilitator and to establish communication between the first communications interface and the second communications interface upon receipt by the second communications interface of the identity of the first communications interface.

53.A communication system according to claim 50 or claim 51 , wherein the first and second communications interfaces are provided as a single unit, such that the coupling of the first communications interface with the second communications interface is provided integral within said single unit,

54.A communication system according to any one of the claims 50 to 52, wherein the first communications interface and the second communications interface are provided remote from each other, .and wherein the second communications interface is operable to establishing a fourth call leg between the first communications interface and the second communications interface prior to establishing the third call leg to couple the first communications interface and the second communications interface, and wherein the first communications interface is operable to bridge the first call leg and the fourth calj leg at the first communications interface, and the second communications interface is operable to bridge the third call leg and the fourth call leg at the second communications interface to thereby couple the first call leg and the third call leg via the first communications interface, the second communications interface and the fourth call leg to thereby establish communication between the first telephony device and the second telephony device.

55.A communication system according to claim 37, wherein the at least one communications Interface is arranged to storing audio or other multimedia information received from said second telephony device, said audio or multimedia forming said communications data routed by said at least one communications interface.

56.A communication system according to claim 55, wherein the at least one communications interface is operable to transmitting notification from said 5 at least one communications interface to said communications facilitator of the storage of said audio or multimedia information,

57. A communication system according to claim 55 or claim 56, wherein the at least one communications interface is arranged to receive a request from said first telephony device for retrieval of said audio or multimedia 0 information.

58. A communication system according to any one of claims 55 to 57, wherein the at least one communications interface is operable to transmit said stored audio or multimedia information from said at least one communications interface to said first telephony device.

5 59.A communication system according to any one of claims 55 to 58, wherein the system includes a first communications interface and a second communications interface, and the call data relating to the call initiated by the second telephony device is communicated to the first communications interface, the first communications interface being operable to transmit said Q stored audio or multimedia information from said first communications interface to said second communications interface.

60.A communication system according to claim 59 wherein, the first communications interface is operable to transmit notification from said first ' communications interface to said second communications interface of the 5 storage of said audio or multimedia information.

61. A cellular radio telephone for communication with a telephony device, the cellular radio telephone being operable, in response to a signal from a remote communications facilitator, to communicate with at least a first communications interface to establish a first call leg, the first communications interface being selectable by the communications facilitator, whereby the at least a first communications interface is arranged for communication, with the telephony device to establish a second call leg, and whereby the first call leg is bridged to the second call leg thereby establishing communication between the cellular radio telephone and the telephony device via the communications interface.

62.A cellular radio telephone according to claim 61 , arranged for communication with the call facilitator, and operable to transmit a request to the communications facilitator to establish communication with the telephony device, the cellular radio telephone being further operable, in response to a signal from the communications facilitator, to establish communication with the first communications interface thereby establishing the first call leg.

63.A communications interface for use in establishing communication between a telephony device and a cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, and the communication between the cellular radio telephone and the telephony device comprise at least two call legs, wherein the communications interface is operable to bridge the at least two call legs to establish communication between the cellular radio telephone and the telephony device via the communications interface.

64.A communications interface according to claim 63 arranged for communication with another communications interface to define a further call leg between said communication interfaces.

65. A communications interface according to claim 62 or claim 63, operable to store multimedia information received from the telephony device.

66.A communications interface according to claim 65, wherein the communications interface is further operable to transmit the multimedia information to the first communications interface for storage therein, and the cellular radio telephone is operable to retrieve the stored multimedia information from the first communications interface.

67.A communications facilitator for establishing communication between a telephony device and a cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, wherein the communications facilitator is operable to initiate communication between the cellular radio telephone and a first communications interface, thereby establishing a first call leg between the cellular radio telephone and the first communications interface, the communications .facilitator being further operable to initiate communication between the first communications interface and the telephony device to thereby establish a second call leg, whereby the first call leg and the second call leg can be bridged to thereby establish direct communication between the cellular radio telephone and the telephony device via the communications interface.

68.A communications facilitator according to claim 67, wherein the communications facilitator is operable to receive a request from the cellular radio telephone to establish communication with the telephony device, and to transmit details of the request, in response to the request, to the first communications interface and to signal the cellular radio telephone to call the first communications interface, to thereby establish the first leg.

69. A communications facilitator according to claim 67 or claim 68, wherein the communications facilitator is further operable to initiate a communication between the first communications interface and a second communications interface arranged for communication with a telephony device via third call leg, the communications facilitator being operable to transmit details of the first communications interface to the second communications interface so that the first and second communications interfaces can establish communications therebetween thereby establishing a fourth call leg, so that the first call leg and the fourth call leg can be bridged via the first communications interface, and the third call leg and the fourth call leg can be bridged via the second communications interface, 'thereby establishing direct communication between the cellular radio telephone and the telephony device via the first and second communications interfaces.

70. A communications facilitator according to any one of claims 67 to 69 wherein the communications facilitator is operable to select the communications interface in accordance with predetermined conditions.

71. A communications facilitator according to any one of claims 67 to 70 including storage means for storing data relating to calls established

• between the cellular radio telephone and the telephony device.

72.A communications facilitator according to any one of claims 67 to 71^', wherein the communications facilitator is further operable to transmit a signal to the cellular radio telephone to communicate with the first communications interface to retrieve multimedia data therefrom.

73.A data communication between a communications facilitator and a cellular radio telephone and at least one communications interface for enabling establishment of communication between a telephony device and the cellular radio telephone, the cellular radio telephone being located remotely from the telephony device, wherein the data communication enables a communications facilitator to initiate communication between the cellular radio telephone and the first communications interface, thereby establishing a first call leg between the cellular radio telephone and the first communications interface, the data communication further enabling the communications facilitator to initiate communication between the first communications interface and the telephony device to thereby establish a second call leg, whereby the first call leg and the second call leg can be bridged to thereby establish direct communication between the cellular radio telephone and the telephony device via the communications interface.

74.A method for establishing communication between a telephony device and a cellular radio telephone substantially as hereinbefore described with reference to the accompanying drawings.

75.A system for establishing communication between a telephony device and a cellular radio telephone substantially as hereinbefore described with reference to the accompanying drawings.

76. A cellular radio telephone for communication with a telephony device substantially as hereinbefore described with reference to the accompanying drawings.

77. A communications interface for use in establishing communication between a telephony device and a cellular radio telephone substantially as hereinbefore described with reference to the accompanying drawings.

78.A communications facilitator for use in establishing communication between a telephony device and a cellular radio telephone substantially as ^• hereinbefore described with reference to the accompanying drawings.