"Method and Apparatus for Forming Communications between Telephony Devices „'>>

Field of the Invention

This invention relates to establishing phone calls between telephony devices particularly using a combination of Public Switched Telephone Network and Voice over Internet Protocol technologies.

Background Art

The following discussion is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the application.

Circuit switching technology used within the Public Switched Telephone Network ("PSTN") is the most commonly used networking technology to offer and support end-to-end voice communication services. Voice over Internet Protocol ("VoIP") is an alternative technology for offering voice communication services with at least one advantage related to the reduced costs associated with using Internet Protocol network technology compared to the PSTN. However, the prerequisites for a user to take advantage of the cost benefits of VoIP, typically includes (i) Internet Protocol access connection at the user premises via an Internet Service Provider, (ii) specialised hardware and software, and (iii) a VoIP service provider. For many users, whether they are residential or business users, it may not be viable or possible to acquire these prerequisites in order to use VoIP technology. Calling card technology is one method whereby this can be achieved but this technology requires the user to perform many steps, for example, dialling one number to access the service, then typing in a personal identification number ("PIN"), then typing in the required destination number.

Disclosure of the Invention

According to the present invention, there is provided a method for establishing communication between a source telephony device and a destination telephony device over a telecommunications network, the method including the steps of:

providing an interface between the source telephony device and the telecommunications network;

initiating a telecommunications channel between the interface and a call server to transmit call data thereto, the call data including caller identity information;

nominating an intermediary device within the telecommunications network;

terminating the telecommunications channel between the interface and the call server; and

routing the communication between the source telephony device and the destination telephony device routed via the nominated intermediary device after termination of the telecommunications channel.

Preferably, the method further comprises the steps of:

transmitting additional call data from the call server to the interface via the telecommunications channel, the additional call data including nominated intermediary device information;

initiating a first call leg between the interface and the intermediary device in accordance with the received nominated intermediary device information;

initiating a second call leg between the nominated intermediary device and the destination telephony device, whereby the first and second call legs route the communication between the source telephony device and the destination telephony device;

coupling the first and second call legs at the nominated intermediary device; and

transferring control of communication from the interface to the source telephony device to thereby route the communication between the source telephony device and the destination telephony device, via the nominated intermediary device.

Preferably, the telecommunications channel is terminated after transmitting the additional call data to the interface from the call server.

Preferably, the method further includes the steps of: transmitting a call signal to the interface from the call server via the telecommunications channel; and initiating the first call leg by means of the interface calling the nominated intermediary device in response to the call signal, and in accordance with the nominated intermediary device information.

Preferably, the first call leg is initiated after termination of the telecommunication channel.

Preferably, the call data includes destination telephony device information, and the method includes the further steps of: transmitting the destination telephony device information to the nominated intermediary device from the call server; and initiating the second call leg on the basis of the destination telephony device information received by the nominated intermediary device from the call server.

Preferably, the nominated intermediary device is a third-party device and the transmitted additional call data includes third-party call data necessary for establishing communication with the third-party device via the first call leg.

Alternatively, the method further comprises the steps of:

initiating a first call leg between the interface and the nominated intermediary device;

initiating a second call leg between the nominated intermediary device and the destination telephony device;

coupling the first and second call legs at the nominated intermediary device;

transferring control of communication from the interface to the source telephony device to thereby establish the communication between the source telephony device and the destination telephony device;

sending a first signal to the nominated intermediary device to initiate the first call leg;

transmitting additional call data including interface information from the call server to the nominated intermediary device;

whereby the first call leg is initiated by the nominated intermediary device calling the interface in response to the first signal from the call server, and in accordance with the interface information.

Preferably, the telecommunications channel is terminated upon receipt of the first signal by the nominated intermediary device.

Preferably, the additional call data further includes destination telephony device information, and the method further includes the step of initiating the second call leg in accordance with the destination telephony device information.

Preferably, the method further including the steps of: transmitting a second signal to the interface from the call server via the telecommunications channel, the second signal indicating to the interface that the first call leg is to be initiated by means of the nominated intermediary device calling the interface.

Preferably, the second signal is a call-back command from the call server.

Alternatively, the second signal is a signal indicating the telecommunications channel has been unanswered.

Preferably, the method further includes the steps of: transmitting destination telephony device information from the interface to the nominated intermediary device, and initiating the second call leg on the basis of the destination telephony device information received from the interface.

Preferably, the nominated intermediary device is nominated on the basis of predetermined criteria.

Preferably, the predetermined criteria include one or more of source telephony device information, destination telephony device information, and user profile information.

Preferably, the telecommunications channel is initiated in response to the detection of predetermined destination telephony device call data input to the interface from the source telephony device.

Preferably, the call server and the nominated intermediary device are connected via the Internet.

Preferably, the first call leg is initiated over the Internet.

Preferably, the second call leg is initiated over the Internet.

In accordance with a second aspect of the invention, there is provided a telecommunications system for establishing a communication between a source telephony device and a destination telephony device over a telecommunications network, the telecommunications system comprising:

an interface coupled between the source telephony device and the telecommunications network;

at least one intermediary device; and

a call server

the interface being operable to initiate a telecommunications channel between the interface and the call server to transmit call data thereto, the call data including caller identity information; and

the call server being operable to:

nominate one of the at least one intermediary device within the telecommunications network through which the communication between the source telephony device and the destination telephony device is routed on the basis of the call data and information stored at the call server;

and to terminate the telecommunications channel between the interface and the call server prior to routing of the communication between the source telephony device and the destination telephony device.

Preferably, the call server is operable to transmit additional call data to the interface via the telecommunications channel, the additional call data including nominated intermediary device information; and the interface is operable to initiate a first call leg between the interface and the intermediary device on the basis of the received nominated intermediary device information; and the call server is operable to: initiate a second call leg between the intermediary device and the destination telephony device, whereby the first and second call legs route the communication between the source telephony device and the destination telephony device; and couple the first and second call legs at the intermediary device, and the interface is further operable to transfer control of communication from the interface to the source telephony device to thereby route the communication between the source telephony device and the destination telephony device, via the nominated intermediary device.

Preferably, the telecommunications channel is terminated after transmitting the additional call data to the interface from the call server.

Preferably, the call server is further operable to transmit a call signal to the interface via the telecommunications channel and the interface is operable to initiate the first call leg in response to the call signal, and in accordance with the nominated intermediary device information.

Preferably, the first call leg is initiated after termination of the telecommunication channel.

Preferably, the call data includes destination telephony device information, and the call server is further operable to transmit the destination telephony device information to the intermediary device; and the nominated intermediary device is operable to initiate the second call leg on the basis of the destination telephony device information received by the intermediary device from the call server.

Preferably, the nominated intermediary device is a third-party device and the transmitted additional call data includes third-party call data necessary for establishing communication with the third-party device via the first call leg.

Preferably, the nominated intermediary device is operable to: initiate a first call leg between the interface and the nominated intermediary device; initiate a second call leg between the nominated intermediary device and the destination telephony device; and couple the first and second call legs, the interface being further operable to transfer control of communication from the interface to the source telephony device to thereby route the communication between the source telephony device and the destination telephony device, and the call server being further operable to transmit additional call data including interface information to the nominated intermediary device and to send a first signal to the nominated intermediary device whereby the nominated intermediary device is operable to call the interface in response to the first signal from the call server, and in accordance with the interface information.

Preferably, the telecommunications channel is terminated upon receipt of the first signal by the intermediary device.

Preferably, the additional call data further includes destination telephony device information, and the second call leg is initiated in accordance with the destination telephony device information.

Preferably, the call server is further operable to transmit a second signal to the interface via the telecommunications channel, the second signal indicating to the interface that the first call leg is to be initiated by means of the nominated intermediary device calling the interface.

Preferably, the second signal is a call-back command from the call server.

Alternatively, the second signal is a signal indicating the telecommunications channel has been unanswered.

Preferably, the interface is further operable to transmit destination telephony device information to the nominated intermediary device, and the nominated intermediary device is operable to initiate the second call leg on the basis of the destination telephony device information received from the interface.

Preferably, the nominated intermediary device is nominated on the basis of predetermined criteria.

Preferably, the predetermined criteria include one or more of source telephony device information, destination telephony device information, and user profile information.

Preferably, the telecommunications channel is initiated in response to the detection of predetermined destination telephony device call data input to the interface from the source telephony device.

Preferably, the call server and the nominated intermediary device are connected via the Internet.

Preferably, the first call leg is initiated over the Internet.

Preferably, the second call leg is initiated over the Internet.

In accordance with a third aspect of the present invention, there is provided an interface for a telecommunications system for establishing a communication between a source telephony device and a destination telephony device over a telecommunications network, coupled between the source telephony device and the telecommunications network, the telecommunications system further including a call server and at least one nominated intermediary device through which the communication between the source telephony device and the destination telephony device is routed on the basis of the call data and information stored at the call server, wherein the interface is operable to initiate a telecommunications channel between the interface and the call server to transmit call data thereto, the call data including caller identity information; and the telecommunications channel between the interface and the call server being terminated prior to routing of the communication between the source telephony device and the destination telephony device.

Preferably, the interface is operable to initiate a first call leg between the interface and the nominated intermediary device, the first call leg being coupled, at the nominated intermediary device, to a second call leg for establishing the communication between the source telephony device and the destination telephony device.

Preferably, the first call leg is initiated in response to a signal from the call server.

Preferably, the first call is initiated by the interface to a third-party device.

Preferably, the interface is arranged to receive a call from the nominated intermediary device to establish the first call leg.

Preferably, the interface is further operable to transmit destination telephony device information to the nominated intermediary device in response to the call received from the nominated intermediary device.

In accordance with a fourth aspect of the present invention, there is provided a call server for a telecommunications system for establishing a communication between a source telephony device and a destination telephony device over a telecommunications network, the telecommunications system further including an interface coupled between the source telephony device and the telecommunications network and operable to initiate a telecommunications channel between the interface and the call server to transmit call data thereto, the call data including caller identity information, and at least one intermediary device, the call server being operable to nominate one of the at least one intermediary device within the telecommunications network through which the communication between the source telephony device and the destination telephony device is routed on the basis of the call data and information stored at the call server, and to terminate the telecommunications channel between the interface and the call server prior to routing of the communication between the source telephony device and the destination telephony device.The present invention provides advantages over known telecommunications systems. The call server is not, unlike some prior art systems, a conventional local exchange that can be used to terminate calls from telephony devices, but is rather, a server that can be located anywhere on the Internet. In contrast in the present invention, the call is routed via the intermediary device - that is a call bridge. Whereas, in conventional systems, calls tend to be routed and terminated at a conventional exchange which then requires additional actions to be carried out, the present invention does not.

The intermediary device, e.g. third party device or a call bridge, can be located anywhere, as can the call server. This is particularly applicable to the use of the Internet which means that these components can be located anywhere on the Internet.

The present invention therefore provides a method whereby users that are not directly connected to the Internet (and only connected via the PSTN), can more simply, reliably and with reduced steps, use VoIP technology in order, for example, to reduce call tariffs than would otherwise have been the case if only the PSTN were used.

Brief Description of the Drawings

The invention will now be described, by way of example only, be reference to the accompanying drawings, of which:

Figure 1 schematically illustrates the architecture of a telephone communication system of the present invention;

Figure 2 schematically illustrates a first embodiment of the invention for the establishment of two call legs between a source and destination telephony devices using the system of Figure 1 ;

Figure 3 is a sequence diagram for the establishment of a call between a source telephony device and a destination telephony device using the system as illustrated in Figure 2;

Figure 4 schematically illustrates a second embodiment of the invention for the establishment of a single call leg between a source and destination telephony devices using the system of Figure 1 ;

Figure 5 is a sequence diagram for the establishment of a call between a source telephony device and a destination telephony device using the system as illustrated in Figure 4;

Figure 6 schematically illustrates a third embodiment of the invention for the establishment of two call legs between a source and destination telephony devices using the system of Figure 1 ;

Figure 7 is a sequence diagram for the establishment of a call between a source telephony device and a destination telephony device using the system as illustrated in Figure 6;

Figure 8 is a schematic illustration of a PSTN Telephony Interface device used in the telephone communication system of Figure 1 ;

Figure 9 schematically illustrates a fourth embodiment of the invention for the establishment of two call legs between a source and destination telephony devices using the system of Figure 1 ;

Figure 10 is a sequence diagram for the establishment of a call between a source telephony device and a destination telephony device using the system as illustrated in Figure 9;

Best Mode(s) for Carrying Out the Invention

Throughout the specification and claims, 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, computer servers or any other such devices.

Figure 1 illustrates schematically the components of one embodiment of a telephone communication system 1 of the present invention.

The telephone communication system 1 comprises a call server 2, a call bridge 3, a PSTN Telephony Interface Device ("PTID") 4 and at least two media gateways 5. It will be appreciated from the following description that other numbers of call servers 2, call bridges 3, PTIDs 4 and media gateways 5 can be used.

A PTID 4 is hardware or software, or a combination of hardware and software components, that provides an interface between the source telephony device 6 and the PSTN 7 with which the source telephony device 6 uses to make and receive calls in a usual, known, manner. The PTID 4 comprises memory 8, and other associated software and hardware to enable the functionality of the PTID 4 as will be described in further detail below. The PTID 4 is coupled to the source

telephony device 6 and is functional to detect and record in the PTID memory 8 information inputted by a user of the source telephony device 6. In this embodiment, the PTID 4 detects the information inputted by a user by detecting the DTMF tones transmitted by the source telephony device 6, as is well known in the art. Usually the information inputted by the user at the source telephony device 6 relates to the destination phone number of the destination telephony device 11 that the user intends to establish a telephone communications with.

The PTID 4 also interfaces to the PSTN 7 and is functional to establish regular telephone communication channels through the PSTN 7 to other telephony devices. This can be achieved in any suitable, known, way. The PTID 4 is also functional to establish a bi-directional communications channel between itself and the call server 2. This communications channel will be referred to as the PTID/Call Server Communications Channel ("PCSCC") 10. This will be described in further detail below.

The call bridge 3 acts as an intermediary device that enables routing of a call from the source telephony device 6 to the destination telephony device 11. The call bridge 3 is typically a server that can be located anywhere on the Internet.

In an alternative embodiment, the PCSCC 10 can be a unidirectional telecommunications channel for sending data from the PTID 4 to the call server 2. In this embodiment, the unidirectional nature of the PCSCC 10 is able to communicate caller ID (CID) information regarding the telephone number N _s of the source telephony device 6. It is only the telephone number N ₅ that is transmitted via the PCSCC 10 in this embodiment. Other data, for example, the telephone number N _d of the destination telephony device 11 is transmitted to the call bridge 3 via a first call leg 23 - as will be described in more detail below.

The PTID 4 and the call server 2 are able to communicate with each other via the PCSCC 10 for the purpose of aiding telephony communication establishment from the source telephony device 6 to other telephony devices, such as a destination telephony device 11.

The PCSCC 10 is any low cost communications channel suitable for the transmission of data information, for example a 1-800 telephone service circuit. Where the PCSCC 10 is a unidirectional telecommunications channel, it can be of any suitable type that allows the communication of CID information.

In those embodiments described herein where a bi-directional PCSCC 10 is established, once the PCSCC 10 is established, the PTID 4 is able to transmit/receive call information to/from the call server 2. This call information can be transmitted by DTMF tones or via modem data communications, in a manner that is known to persons skilled in the art. This call information can include, for example, details of the phone number of the destination telephony device 11 , that the user at the source telephony device 6 requires to establish a telephony communications with. The call server 2 uses this information and assists in establishing telephone communications between the source telephony device 6 and other destination telephony devices 11.

After receiving certain instructions from the call server 2 via the PCSCC 10, the PTID 4 can, in some instances, also be responsible for initiating telephone communications to directed call bridges 3 or other telephony devices. The PTID 4 may also have features that detect calls to and from local devices in order to allow the source telephony device 6 to operate as it normally would.

For a uni-directional PCSCC 10, once the CID information is transmitted to the call server 2, the call server 2 assists in establishing other communications channels between call bridges 3 and the PTID 4. Using these additional communications channels, the PTID 4 is able to transmit and receive call information, for example through the use of DTMF tones or modem data communications to and from a call bridge 3.

The call server 2, under control of software, co-ordinates the establishment of telephone communications between two telephony devices 6, 11 via the call bridge(s) 3 or other telephony devices, as will be described in further detail below.

Communication between the call server 2, and the call bridges 3, and between the call bridges 3 and the PSTN's 7 is usually established via the Internet 9, although other suitable communications networks and protocols could be used.

The call server 2 maintains a database 12 which contains information regarding current call costs associated with multiple telephone or VoIP service providers. The call server 2 also maintains a database 13 relating to the quality and/or availability of the voice service being offered by telecommunications service providers (for example, VoIP service providers). This information is used to establish optimum service operating behaviour, for example, by choosing which VoIP service operator to use for establishing call legs so as to minimise call costs or by choosing which VoIP service operator to use for establishing call legs so as to maximise call quality. The call server 2 can also use this database information to make decisions about which party, that is the PTID 4 or the call bridge 3 should initiate telephony communications so as to minimise calling costs or to maximise call quality. The call server 2 is also responsible for the making call bridge telephone number selection choices so as to minimise call costs. The informational outcome of some or all of these decisions can also be signalled back to the PTID 4 via the established PCSCC 10,where the PCSCC 10 is a bidirectional channel, whereby the PTID 4 will use this information to function in such a way so as to establish optimum or predefined service behaviour for the user located at the source telephony device. The call server 2 also keeps a database 14 of all the call bridges 3 within the telecommunications system 1 and all their associated callable phone numbers. The call server 2 can also keep databases 15 storing additional information such as customer preferences related to calls that allow it to make decisions about setting up calls, for example, a preference to minimise call costs or a preference to maximise call quality. As mentioned above, the call servers 2 receive messages from the PTID 4 via the PCSCC 10 indicating the requirement for a new call establishment.

After receiving call details from the PTID 4 (such as the phone number of the destination telephony device), it is the function of the call server 2 to facilitate the end to end telephone communications establishment between the source telephony device 6 and the destination telephony device 11. This can proceed in a

number of ways, depending on the preference of the user of this telephone communications system 1. For example, the call could proceed at least in the following four ways:

1. In a first embodiment, illustrated schematically in Figure 2, the call server 2 instructs the PTID 4 to initiate a first call leg 16 to a nominated call bridge

3. The PTID 4 then dials the necessary number to call the nominated call bridge 3 and transfers the communications channel to the source telephony device 11. In this case it is also the function of the call server 2 to instruct the nominated call bridge 3 (typically using the Internet Protocol over the Internet) to initiate a second call leg 17 between the nominated call bridge

3 and the signalled destination telephony device 11 using a specified VoIP service provider (VSP). The call bridge 3 is then functional to bridge the two call legs of the call thereby creating an end to end telephony communications between the source telephony device 6 and the destination telephony device 11.

2. In a second embodiment, illustrated schematically in Figure 4, the call server 2 instructs the PTID 4 to initiate a call to a nominated 3 ^rd party telephony device 18, such as a calling card service device, and containing the necessary information to successfully complete the call (for example, personal identification numbers or PIN). The PTID 4 then dials the necessary numbers to connect to the 3 ^rd party telephony device 18 in order to establish the call to the destination telephony device 11 and then transfers control of the call to the source telephony device thereby creating an end to end telephony communications between the source telephony device 6 and the destination telephony device 11.

3. In a third embodiment, illustrated schematically in Figure 6, the call server 2 instructs a nominated call bridge 3 (typically using the Internet Protocol over the Internet) to initiate a first call leg between the nominated call bridge 3 and the source telephony device 6 using a specified VoIP service provider (VSP). The call server 2 also instructs the same nominated call bridge 3 (typically using the Internet Protocol over the Internet) to initiate a

second call leg between the nominated call bridge 3 and the signalled destination telephony device 11 using a specified VoIP service provider (VSP). The call bridge 3 is then functional to bridge the two call legs of the call thereby creating an end to end telephony communications between the source telephony device 6 and the destination telephony device 11.

4. In a fourth embodiment, illustrated schematically in Figure 9, and similar to the third embodiment the call server 2 instructs the nominated call bridge 3 (typically using the Internet Protocol over the Internet 9) to initiate a call between the nominated call bridge 3 and the signalled source telephony device 6 using a specified VoIP service provider (VSP). In this embodiment, however, the details of the source telephony device are obtained by simply recording CID information from a call launched from the PTID 4 using a unidirectional PCSCC telecommunications channel.

In all the embodiments, the call bridge 3 and the third party telephony device 18 act as an intermediary device through which the communication between the source telephony device 6 and the destination telephony device 11 is routed.

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. There need be only one call server 2 for the telephone communications 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 6, 11 operate in conventional networks such as PSTN and cellular radio telephone networks.

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

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

The call bridge 3, under control of software, is operable to receive or make call legs as instructed by the call server 2. It is also able to "bridge" call legs such that

the phone call between the source telephony device 6 and the destination telephony device 11 is perceived to be direct. Phone calls made by the call bridge 3 can be via a circuit switched network such as a PSTN or can be via the Internet using, for example 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), Session Initiation Protocol (SIP), H.323, etc for establishing VoIP communications is well known and need not be further described herein except as is relevant to the present invention.

For the purposes of lowering the cost of establishing and maintaining call legs, it is preferable to use the Internet and VoIP technology where possible. Ideally, there will one or more call bridges 3 located in each country.

Each call bridge 3 will be identified with a unique identifier CS, and be callable via a set of Kj ( where i is an integer greater than zero) telephone numbers NCB^ (k = 1 ,2, ... Kj), for example through the use of Direct Inward Dialling (DID) numbers or 1 -300 or 1 -800 telephone services or a combination of these.

In order to couple PSTN calls to VoIP (and vice versa) the media gateways 5 are used. The use of media gateways for such coupling is well known and, as such, need not be described in any further detail herein.

The different embodiments of the invention will now be described in more detail.

In the first embodiment of the invention, one method for making a call between a source telephony device 6 and a destination telephony device 11 , such a fixed landline phone, or a mobile phone, using the telephone communications system 1 of the present invention will now be described, and as illustrated in Figures 2 and 3.

The source telephony device 6 is connected to a PTID 4 which is also interfaced to a PSTN 4 that the source telephony device 6 uses to make telecommunications calls.

To make a telephone call, the user at the source telephony device 6 lifts the handset (or equivalent action) and dials the phone number of the destination telephony device 11 in the usual way.

The PTID 4 is then operable to perform the following operations in sequence:

a) Detect the source telephony device 6 becoming "off-hook" and proceed to detect and record into memory 8 the destination telephony device phone number, N _d dialled by the user at the source telephony device 6.

b) Upon recording of the destination telephony device phone number N _d , if the number is recognised as a telephone number that will benefit from the use of the telephone communication system 1 of the present invention, for example, a long-distance or mobile phone number, then the PTID 4 is operable to establish a PCSCC 10 with the call server 2, using a suitable low cost telecommunications communications channel such as a pre-established 1-800 service, or otherwise.

c) Upon establishment of the PCSCC 10 to the call server 2 the PTID 4 sends a short message (for example, using DTMF tones or via modem data communications) to the call server 2 with the call details, including the recorded destination telephony device phone number, Nφ

At the call server 2:

Upon receiving the request from the PTID 4 for establishing a PCSCC 10 the call server 2 records the Caller ID of source telephony device phone number into λ/ _s , that is the call server 2 notes the caller ID of the source telephony device 6 and stores this as source telephony device number N ₃ at the call server 2. The request from the PTID 4 may be a ringing alert from the 1-800 service or any other suitable request. If the source telephony device phone number N ₃ corresponds to that of an authorised user then the call server 2 connects to the PTID 4, thereby establishing the PCSCC 10.

Upon successful establishment of the PCSCC 10, the call server 2 detects and records the destination telephony device phone number, N _d transmitted by the PTID 4. Based on the values of the source telephony device phone number N _s , and the destination telephony device phone number N _d and any user profile information, the call server 2 will nominate a suitable call bridge 3, with the identifier CB _j , that is callable via at least one telephone number NCB _jιk . Preferably, this number NCB _jk will be one that will incur a small or minimal call cost when the PTID 4 establishes communication with call bridge CB _j via this number NCB _iιk . In addition, based on the value of the destination telephony device phone number N _d and the user service requirements (for example, call cost minimisation or call quality), the call server 2 will nominate a VoIP service provider with the identifier VSP _d that call bridge CB _j will use to establish a second call leg 17, between call bridge CB _j and the destination telephony device 11 , of the end to end communications. The call server 2 will proceed according to the following pseudo code:

i. Signal to call bridge CB _j (via Internet Protocol or otherwise) and transmit the source telephony device phone number N ₈ (and possibly other identifiers that uniquely identify the user), the destination telephony device phone number N _d , the nominated call bridge number NCB _Jιk , the VoIP identifier VSP _d that is to be used to establish the second call leg 17, together with a uniquely generated CALLJD identifying this call to call bridge CB _j .

ii. Transmit to the PTID 4 via the PCSCC 10 a "call in-direct" command

iii. Transmit to the PTID 4 via the PCSCC 10 the telephone number NCB _jιk of nominated call bridge CBj.

iv. The call server 2 may then transmit other information and updates to the PTID 4 as required for its ongoing operations. When this is completed the call server 2 terminates PCSCC 10 between the call server 2 and the PTID 4.

v. Upon call response status from call bridge CB _j or timeout

IF call bridge 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

END IF

At the PTID 4:

On the PCSCC 10, and upon detecting the "call in-direct" command from the call server 2, the PTID 4 receives and stores in memory 8 the telephone number λ/Cβ/, _f cθf nominated call bridge CS ₇ associated with the call from the call server 2. The "call in-direct" command instructs the PTID 4 that it is to call-in to call bridge CS ₇ . At this stage the PTID 4 may also receive other information from the call server 2. When this is complete the PTID 4 detects for the termination of the PCSCC 10 and then immediately proceeds to establish the first call leg 16 to call bridge CB _j using the telephone number NCBJX The PTID 4 then immediately proceeds to transfer control of the call to the source telephony device 6, by which audio signals are passed through the PTID 4 to the source telephony device 6. The effect of this is that the source telephony device 6 and the PSTN 7 appear directly connected.

At call bridge CBf

Upon receiving the message from the call server 2, call bridge CB _j maintains in memory a mapping between the transmitted source telephony device phone number N _s , the transmitted destination telephony device phone number N _d and the transmitted VoIP service provider identifier VSP _d that is to be used to establish the second call leg 17 {λ/ _s , N _d , VSP _d }. It is then possible to establish the first call leg 16 and a second call leg 17 that will constitute the communications between the source telephony device 6 and the destination telephony device 11 in the following manner:

o Wait for next incoming call from the source telephony device 6 on the telephone number NCB _jιk

Record the caller ID information present into CID for the next call on the telephone number NCB _jιk so that the call bridge 3 identifies the caller ID of the incoming call from the PTID 4 and records it as CID. At this stage, the call is coming from the

PTID 4. IF call bridge CB _j has a defined mapping for {CID , N _d , VSP _d } THEN

') o Make a call to the destination telephony device 11 having telephone number N _d using the VoIP service provider having the identifier VSP _d , the details of which were transmitted by the call server 2, and information contained in {CID , N _d , VSP _d }.

IF call with N _d is NOT RINGING THEN

o Alert BUSY or otherwise detected state to the source telephony device 6

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

ENDIF

ELSE IF call with destination telephony device N _d is RINGING THEN

Alert the source telephony device 6 with RINGING

Wait for answer at the destination telephony device 11

If the destination telephony device 11 with the telephone number N _d answers (and thereby establishes the second call leg 17) THEN

o Answer the call from the source telephony device (and thereby establishing the first call leg 16).

o Bridge the two call legs 16, 17 such that the source telephony device 6 and destination telephony device 11 perceive the call to be direct.

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

ENDIF

ENDIF

Upon the event that either source telephony device 6 or the destination telephony devices 11 terminates the call or the call attempt process is terminated for any reason, then 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 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.

In a second embodiment of the invention, one method for making a call between a source telephony device 6 and a remote or destination telephony device 11 , such as a fixed landline phone, or a mobile phone, using the communications system of the present invention will now be described, and as illustrated in Figures 4 and 5:

The source telephony device 6 is connected to a PTID 4 which is also interfaced to a PSTN 4 that the source telephony device 6 uses to make telecommunications calls.

To make a telephone call, the user at the source telephony device 6 lifts the handset (or equivalent action) and dials the phone number of the destination telephony device 11 in the usual way.

The PTID 4 is then operable to perform the following operations in sequence:

a) Detect the source telephony device 6 becoming "off-hook" and proceed to detect and record into memory 8 the destination telephony device phone number, N _d dialled by the user at the source telephony device 6.

b) Upon recording of the destination telephony device phone number N _d , if the number is recognised as a telephone number that will benefit from the use of this telephone communications system 1 , for example because it is a mobile 'phone number or a long distance phone number, then the PTID 4 is operable to establish a PCSCC 10 with the call server 2, using a suitable low cost telecommunications communications channel such as a pre-established 1-800 service, or otherwise.

c) Upon establishment of the PCSCC 10 to the call server 2 the PTID 4 sends a short message (for example, using DTMF tones or via modem data communications) to the call server 2 with the call details, including the recorded destination telephony device phone number, N _d .

At the call server 2:

Upon receiving the request from the PTID 4 for establishing a PCSCC 10 the caller server 2 records the Caller ID of the source telephony device 6 into N ₃ . The request from PTID 4 may be a ringing alert from the 1-800 service or any other suitable request. If N ₃ corresponds to an authorised user then the call server 2 connects to the PTID 4 thereby establishing the PCSCC 10. Upon successful establishment of the PCSCC 10, the call server 2 detects and records the destination telephony device phone number, N _d transmitted by the PTID 4. Based on the values of N ₅ , N _d and any user profile information, the call server 2 will nominate a suitable third-party device 18 callable via a number N _d . Preferably, N _d is one that incurs a small or minimal call cost when the PTID 4 establishes communication with the destination telephony device 11 using this number. The call server 2 will proceed according to the following pseudo code:

i. Transmit to the PTID 4 via the PCSCC 10 a "call direct" command

ii. Transmit to the PTID 4 via the PCSCC 10 the telephone number N _d of the third-party device 18 and any other associated PIN numbers if required to establish a call between the PTID 4 and the third-party device 18

iii. The call server 2 may then transmit other information and updates to the PTID 4 as required for its ongoing operations. When this is completed the call server 2 terminates the PCSCC 10 between the call server 2 and the PTID 4.

At the PTID 4:

On the PCSCC 10, and upon detecting the "call direct" command from the call server 2, the PTID 4 receives and stores in memory 8 the telephone number N _d and any other associated PIN numbers of the third-party device 18. At this stage the PTID 4 may also receive other information from the call server 2. When this is complete the PTID 4 detects for the termination of the PCSCC 10 by the call server 2 and then immediately proceeds to establish a first call leg 19 to the third- party device 18 having the telephone number N _d . Upon answer the third-party device 18, the PTID 4 then immediately proceeds to send (via DTMF tones, or any other suitable means) any PIN number information (if required and as supplied by the call server 2) followed by (again via DTMF or any other suitable means) the telephone number N _d of the destination telephony device 11. Upon completion of this task, the PTID 4 transfers control of the call from the PTID 4 to the source telephony device 6, by which audio signals are passed through the PTID 4 to the source telephony device 6.

The rest of the call i.e. the establishment of a second call leg 22 to the destination telephony device 11 is as in conventional third-party telephone calls, and, as such need not be described in any further detail herein.

In a third embodiment of the invention, a method for making a call between a source telephony device 6 and a destination telephony device 11 , such as a fixed landline phone, or a mobile phone, using the telephone communications system 1 of the present invention will now be described, and as illustrated in Figures 6 and 7:

The source telephony device 6 is connected to a PTID 4 which is also interfaced to a PSTN 4 that the source telephony device 6 uses to make telecommunications calls.

To make a telephone call, the user at the source telephony device 6 lifts the handset (or equivalent action) and dials the phone number of the destination telephony device 11 in the usual way.

The PTID 4 is then operable to perform the following operations in sequence:

a) Detect the source telephony device 6 becoming "off-hook" and proceed to detect and record into memory 8 the destination telephony device phone number, N _d dialled by the user at the source telephony device 6.

b) Upon recording of the destination telephony device phone number N _d , if the number is recognised as a telephone number that will benefit from the use of the telephone communications system 1 of the present invention, such as a mobile phone number or a long-distance number, then the PTID 4 is operable to establish a PCSCC 10 with the call server 2, using a suitable low cost telecommunications communications channel such as a pre-established 1 -800 service, or otherwise.

c) Upon establishment of the PCSCC 10 to the call server 2 the PTID 4 sends a short message (for example, using DTMF tones or via modem data communications) to the call server 2 with the call details, including the recorded destination telephony device phone number, N _d .

At the call server 2:

Upon receiving the request from the PTID 4 for establishing a PCSCC 10 the caller server 2 records the Caller ID of the source telephony device 6 into N _s . The request from PTID 4 may be a ringing alert from the 1-800 service or any other suitable request. If N _s corresponds to an authorised user then the call server 2 connects to the PTID 4 thereby establishing the PCSCC 10. Upon successful

establishment of the PCSCC 10, the call server 2 detects and records the destination telephony device phone number, N _d transmitted by the PTID 4. Based on the values of N ₅ , N _d and any user profile information, the call server 2 will nominate a suitable call bridge 3, identified by the identifier CBj that will act a bridge for two call legs 20, 21 that will make up the end-to-end communications between the source telephony device 6 and a destination telephony device 11. Also, based on the value of N _d and the user service requirements (for example, call cost minimisation), the call server 2 will nominate two VoIP service providers that call bridge CB _j will use to establish the two call legs 20, 21 of the end-to-end call. The two VoIP service providers will be identified by identifiers VSP ₅ (for establishing a first call leg 20 between the source telephony device 6 and call bridge CB _j ) and VSP _d (for establishing a second call leg 21 between call bridge CB _j and the destination telephony device 11 ). The call server 2 will proceed according to the following pseudo code:

i. Signal to call bridge CB _j (via Internet Protocol or otherwise) and transmit the source telephony device telephone number N ₃ (and possibly other identifiers that uniquely identify the user), VSP ₃ that is to be used to establish the first call leg 20, the destination telephony device telephone number N _d , the VSP _d that is to be used to establish the second call leg 21 , together with a uniquely generated CALLJD identifying this call to call bridge CB _j .

ii. The call server 2 sends a "call back" command to the PTID 4 via the PCSCC 10. This "call back" command indicates that the PTID 4 is to receive a "call back" call from call bridge CB _j.

iii. Upon call response status from CB _j or timeout

IF CB _j responds with BUSY or NOT AVAILABLE THEN

Send BUSY or NOT AVAILABLE alert to PTID 4 via PCSCC 10

CaII server 2 terminates PCSCC 10 between the call server 2 and the PTID 4.

ENDIF

IF CSy responds with PROCEEDING THEN

Send PROCEEDING alert to PTID 4 via PCSCC 10

Call server 2 terminates PCSCC 10 between the call server 2 and the PTID 4.

ENDIF

IF CSy responds with SUCCESS for this CALLJD THEN

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

At the PTID 4:

On the PCSCC 10, and upon detecting the "call back" command from the call server 2, the PTID 4 proceeds as follows:

Wait for next message from the call server 2 on the PCSCC 10

IF from call server 2 detect BUSY alert or NOT AVAILABLE alert THEN

Alert source telephony device 6 BUSY or NOT AVAILABLE

ENDIF

IF from call server 2 detect PROCEEDING alert THEN

PTID 4 detects for the termination of the PCSCC 10

On the source telephony device side - play "ringing" tones to the source telephony device 6

On the PSTN side wait for next incoming call. When incoming call detected, answer the call and immediately proceed to transfer control of the call from the PTID 4 to the source telephony device 6, by which audio signals are passed through the PTID 4 to the source telephony device 6.

ENDIF

At call bridge CBf

Upon receiving the message from the call server 2, the call bridge CB _j maintains in memory a mapping between the signalled numbers, that is the source telephony device telephone number N ₃ (and possibly other identifiers that uniquely identify the user), the VSP ₃ that is to be used to establish the first call leg

20, the destination telephony device telephone number N _d , and the VSP _d that is to be used to establish the second call leg 21 , {N _s , VSP ₃ , N _d , VSP _d }. It is then possible to establish the two call legs 20, 21 that will constitute the call between the source telephony device 6 and the required destination telephony device 11 in the following manner:

Make a call to the telephone number N _d of the destination telephony device using the signalled VSP _d information contained in [N ₃ , VSP ₃ , N _d , VSP _d }.

IF call with N _d is NOT RINGING THEN

Return BUSY or otherwise detected status associated with this CALLJD to call server 2 and exit

ENDIF

ELSE IF call with destination telephony device N _d is RINGING THEN

Return PROCEEDING status associated with this CALL ID to call server 2

Wait for answer at the telephone destination device 11

If the destination telephony device 11 answers (and thereby establishing the second call leg 21 ) THEN

Play a "connecting, please wait... " voice message to the destination telephony device 11.

Make a call to the telephone number N ₅ of the source telephony device 6 using the VoIP service provider with the identifier VSP ₃ from the information contained in [N ₈ , VSP _s , N _d , VSP _d }.

Upon source telephony device 6 answer (and thereby establishing the first call leg 20), bridge the first and second call legs 20, 21 (such that the source telephony device 6 and destination telephony device 11 perceive the call to be direct).

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

ENDIF

ENDIF

Upon the event that either source telephony device 6 or the destination telephony devices 11 terminates the call or the call attempt process is terminated for any reason, then call bridge CB _j is operable to return TERMINATE status associated with the CALL ID of the terminated call to call server 2.

At the call server 2, and upon receiving the TERMINATE status from call bridge CSy 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 fourth embodiment of the invention, a method for making a call between a source telephony device 6 and a destination telephony device 11 , such as a fixed landline phone, or a mobile phone, using the telephone communications system 1

of the present invention will now be described, and as illustrated in Figures 9 and 10:

The source telephony device 6 is connected to a PTID 4 which is also interfaced to a PSTN 4 that the source telephony device 6 uses to make telecommunications calls.

In this embodiment, each call server 2 will be identified with a unique identifier CSj and be callable via a set of Gj (G ₁ is an integer greater than zero) telephone numbers NCS^g (g = 1 ,2, ... G ₁ ), for example through the use of Direct Inward Dialling (DID) numbers or 1-300 or 1-800 telephone services or a combination of these.

The call bridge 3 is also functional to receive call details from the PTID 4 such as the telephone number N _d , of a destination telephone device 11.

To make a telephone call, the user at the source telephony device 6 lifts the handset (or equivalent action) and dials the phone number of the destination telephony device 11 in the usual way.

The PTID 4 is then operable to perform the following operations in sequence:

a) Detect the source telephony device 6 becoming "off-hook" and proceed to detect and record into memory 8 the destination telephony device phone number, N _d dialled by the user at the source telephony device 6.

b) Upon recording of the destination telephony device phone number N _d , if the number is recognised as a telephone number that will benefit from the use of the telephone communications system 1 of the present invention, such as a mobile phone number or a long-distance number, then the PTID 4 is operable to launch the establishment of a unidirectional PCSCC 10 with the call server 2 by calling a number

NCSj, _g , associated with a call server, or otherwise. If launch of the establishment of a PCSCC 10 is enabled by means of a

telecommunications channel i.e. using the number NCSJ ₉ , then, in order to minimise the cost of using the PCSCC 10, the call server 2 is operable not to 'answer ¹ the call from the PTID 4, but to obtain and record the CID of the source telephony device 6 when the PTID 4 launches the call to the call server 2 and the call is received by the call server 2. The call server 2 then proceeds to 'reject' or terminate the incoming call from the PTID 4. This is achieved by, when the call server 2 has obtained the caller ID CID of the source telephony device 6, then the call server 2 is operable to return a "busy" or equivalent signal. The PTID 4 is then operable to detect this signal which is used by the PTID

4 to determine that the call server 2 has obtained the value of CID without the call server 2 having to answer the PCSCC 10 from the PTID 4.

c) The PTID 4 then, upon rejection of the incoming call by the call server 2, is then operable to wait for the next incoming call from a suitably selected call bridge 3.

At the call server 2:

Upon receiving the call request from the PTID 4 for the establishment of a communications channel via the PCSCC 10, the call server 2 records the CID of the source telephony device into N _s and rejects (i.e. does not answer) the incoming call from the PTID 4 and terminates the call from the PTID 4. If N _s i.e. the telephone number of the source telephony device 6 corresponds to an authorised user, then the call server 2, based on the values of N _s and any user profile information, will nominate a suitable call bridge 3 having the identifier CB, that will act as a call bridge for two call legs 23, 24 that will make up the end-to- end communications between the source telephony device 6 and the destination telephony device 11. Also, based on the value of N _s and the user service requirements (for example, call cost minimisation), the call server 2 will nominate two VoIP service providers that call bridge CB _j will use to establish the two call legs 23, 24 of the end-to-end call. The two VoIP service providers will be identified by identifiers VSP ₅ (for establishing a first call leg 23 between the

source telephony device 6 and call bridge CBy) and VSP _d (for establishing a second call leg 24 between call bridge CB _j and the destination telephony device 11). The call server 2 will proceed according to the following pseudo code:

i. Signal to nominated call bridge CB _j (via Internet Protocol or otherwise) and transmit the source telephony device telephone number N ₅ (and possibly other identifiers that uniquely identify the user), VSP ₃ that is to be used to establish the first call leg 23, VSP _d that is to be used to establish the second call leg 24, together with a uniquely generated CALLJD identifying this call to the call bridge CB _j .

At call bridge CB ₁ :

Upon receiving the message from the call server 2, call bridge CB _j maintains in memory a mapping between the signalled numbers, that is the source telephony device telephone number N ₃ (and possibly other identifiers that uniquely identify the user), the VSP _S that is to be used to establish the first call leg 23, the destination telephony device telephone number N _d , and the VSP _d that is to be used to establish the second call leg 24, [N ₃ , VSP _S , N _d , VSP _d }. Once the value of N _d i.e. the destination telephony device phone number, is obtained from the PTID 4, it is then possible for call bridge CSy to establish the first call leg 23 and the second call leg 24 that will constitute the call between the source telephony device 6 and the required destination telephony device 11 in the following manner:

o Make a call to the telephone number N _s of the source telephony device 6 using the signalled VoIP service provide identifier VSP ₃ contained in {Ns, VSPs, Nd, VSP _d } This call establishes the first call leg 23.

o When the call is answered by the PTID 4, call bridge CB _j detects and records the destination telephony device phone number, N _d transmitted by the PTID 4.

o Once the successful reception of destination telephony device phone number, /V ₄ * from the PTID 4, the call bridge CB _j acknowledges this to the PTID 4 - by transmitting a DTMF sequence such as *** - and places

the value of the destination telephony device phone number N _d into the set {N _S) VSPs, N _d , VSP _d }.

o Make a call to the destination telephony device 11 using the telephone number N _d using the signalled VoIP service provider identifier VSP _d contained in {N _s , VSP ₅ , N _d , VSP _d }. This call establishes the second call leg 25.

o Bridge the first call leg 23 and the second call leg 24, such that the source telephony device 6 and the destination telephony device 11 perceive the call to be direct.

o Upon the event that either source telephony device 6 or the destination telephony device 11 terminates the call or the call attempt process is terminated for any reason, then call bridge CB _j is operable to return TERMINATE status and associated call detail records associated with the CALLJD of the terminated call to the call server 2.

At the PTID 4:

Upon receiving a call from call bridge CB _j , the PTID 4 sends a short message (for example, using DTMF tones or via modem data communications) to call bridge CSy with the call details, including the recorded destination telephony device phone number, N _d . Once the successful transmission of destination telephony device phone number N _d io the call bridge CB _j is acknowledged by call bridge CS ₇ the PTID 4 immediately proceeds to transfer control of the call to the source telephony device 6 by which audio signals are passed through the PTID 4 to the source telephony device 6.

If the PTID 4 detects an incoming call when not expecting a call from call bridge CSy , (i.e. because it has not previously sent a request as defined above to the call server 2) the PTID 4 immediately proceeds to transfer control of the call to the source telephony device 6 (i.e. the source telephony device proceeds to ring in the usual way), because it is assumed that the incoming call is a 'normal' incoming call.