WO2001022700A1

WO2001022700A1 - Telecommunications interface device

Info

Publication number: WO2001022700A1
Application number: PCT/AU2000/001117
Authority: WO
Inventors: Andrew Donaghey
Original assignee: Andrew Donaghey
Priority date: 1999-09-17
Filing date: 2000-09-15
Publication date: 2001-03-29
Also published as: AUPQ294599A0

Abstract

An interface device (3) for placing a call from a local telecommunications device (1) to a remote terminal (5) via a selected telecommunications signal carrier, wherein the local telecommunications device is connected to a local telecommunications exchange, the interface device comprising: memory means (11) for storing a plurality of carrier identifiers, and corresponding variable costing information for each carrier; detecting means (7) for detecting a remote terminal identifier emitted from said local telecommunications device; processing means (9) for comparing the variable costing information corresponding to each stored carrier identifier with call characterisation information and selecting an optimal carrier to establish the call, and for adding a prefix representative of the selected carrier to the remote terminal identifier; and, switching means (6) for sending the prefix and the identifier to the local telecommunications exchange for writing to the telecommunications signal carrier, so that the carrier is able to establish a connection between the local telecommunications device and the remote terminal.

Description

TELECOMMUNICATIONS INTERFACE DEVICE

The present invention relates to interface device for placing a call from a local telecommunications device to a remote terminal, and in particular to an interface device which establishes the connection via a selected telecommunications signal carrier.

Telecommunications devices, such as telephone and facsimile devices, are interconnected and communicate with each other by telecommunication networks, such as public switched telephone networks. In order for a user to establish a connection between a users local telephone device and a remote telephone device, the local telephone device is firstly placed in a active state and a dial mechanism is used to sent a remote terminal identifier signal, either pulse or tone, to a local telephone exchange directly connected to the telephone. The remote terminal identifier signal provides the means to reach the remote telephone device with an assigned number or identifier at the other end of the network. The call itself is switched through a series of telephone exchanges by a telecommunications signal carrier until a dedicated path is created between the local and remote telephone devices. This path stays in place for the duration of the conversation. Only when the parties break the communication are the lines and the telephone exchange equipment free to handle other calls.

In many countries, it is now possible for the establishment of the dedicated path required to switch the call from the calling to the called party to be carried out by one of several telecommunication signal carriers. These carriers generally pay in advance for the right to use a certain quantity, or bandwidth, the overall telephone network capacity. In order to attract customers to entrust the completion and maintenance of their telephone calls to them, the telecommunication signal carriers have developed a variable pricing structure for billing parties wishing to user their service. Many carriers encourage use of their system by offering a lower tariff at night and on weekends. Carriers also offer varying tariffs, depending on the country to which telephone calls are placed. It would therefore be desirable invention to provide a method and device for placing a call from a local telecommunications device to a remote terminal which enables a calling party to take advantage of differing service characteristics, such as pricing tariffs, offered by various telecommunication signal carriers in a simple, convenient and effective manner.

It would also be desirable to provide a method and device for placing a call from a local telecommunications device to a remote terminal which ameliorates or overcomes one or more disadvantages of known call placement methods and devices. With this in mind, one aspect of the present invention provides a method for placing a call from a local telecommunications device to a remote terminal via a selected telecommunications signal carrier, wherein the local telecommunications device is connected to a local telecommunications exchange, the method including the steps of: (a) storing a plurality of carrier identifiers, and corresponding variable costing information for each carrier, in a memory device;

(b) detecting a remote terminal identifier emitted from said local telecommunications device;

(c) comparing the variable costing information corresponding to each stored carrier identifier with call characterisation information and selecting an optimal carrier to establish the calls;

(d) adding a prefix representative of the selected carrier to the remote terminal identifier;

(e) sending the prefix and the identifier to the local telecommunications exchange for writing to the telecommunications signal carrier, so that the carrier is able to establish a connection between the local telecommunications device and the remote terminal.

In one embodiment of the invention, the call characterisation information may be predicted from past use of the local telecommunications device. In another embodiment, the call characterisation information may be provided by a user of the local telecommunications device. The call characterisation information may define a likely duration of the call. The call characterisation information may alternatively define a likely cost of the call.

The variable costing information may relate to the charging information for establishing and/or maintaining the call.

The charging information may be dependent upon any one or more of the destination to which the call is place, the time of day at which the call is placed, the band which sells the connection, duration of the connection or quality of data sent during connection. The method may further include the step of: automatically maintaining the variable costing information in the memory device from a remote central service.

The method may further include the step of maintaining the connection until a selected characteristic of the call matches the call limitation information, whereupon the connection is terminated.

The telecommunications device may be a telephone device, facsimile device or like telecommunications receiver/transmitter.

The local telecommunications device may also be a telephone exchange to which one or more local telecommunications terminals are connected. Another aspect of the present invention provides an interface device for placing a call from a local telecommunications device to a remote terminal via a selected telecommunications signal carrier, wherein the local telecommunications device is connected to a local telecommunications exchange, the interface device comprising: memory means for storing a plurality of carrier identifiers, and corresponding variable costing information for each carrier; detecting means for detecting a remote terminal identifier emitted from said local telecommunications device; processing means for comparing the variable costing information corresponding to each stored carrier identifier with call characterisation information and selecting an optimal carrier to establish the call, and for adding a prefix representative of the selected carrier to the remote terminal identifier; and, switching means for sending the prefix and the identifier to the local telecommunications exchange for writing to the telecommunications signal carrier, so that the carrier is able to establish a connection between the local telecommunications device and the remote terminal.

The processing means may act to predict the call characterisation information from past use of the local telecommunications device.

Alternatively, call characterisation information may be provided by a user of the local telecommunications device.

The processing means may further act to maintain the connection until a selected characteristic of the call matches the call limitation information, whereupon the connection is terminated.

The following description refers in more detail to the various feature of the interface device and method for placing a call of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the invention is illustrated in a preferred embodiment. It is to be understood, however, that the invention is not limited to the preferred embodiment illustrated in the drawings. In the drawings:

Figure 1 is a schematic block diagram of one embodiment of an interface device according to the present invention; and

Figures 2 to 11 are flow charts illustrating the operation of the interface device of Figure 1. Referring now to Figure 1, there is generally shown a telephone device 1 connected to a local telecommunication exchange 2 via an interface device 3.

The telecommunication exchange 2 is connected to a public switched telephone network 4 or other telecommunication network. A remote telecommunication terminal 5, such as a telephone or facsimile device, is connected to the public switched telephone network 4. The telephone device 1 conventionally includes circuitry for enabling the reception and transmission of speech signals, and circuitry for providing a user operable dial mechanism. The dial mechanism enables a user to compose a pulse or tone signal representative of a remote terminal identifier identifying a remote telecommunication terminal with which a connection is to be established in order that voice, video or data can be sent or exchanged. Typically, the remote terminal identifier will include an exchange number portion and a subscriber number portion. The exchange number portion may be a three or four digit code identifying a remote telecommunications exchange to which the remote telecommunications terminal 5 is connected, whilst the subscriber number portion will identify the remote terminal 5 itself. In addition, if a call is to be placed to a location in another country, an international access code portion and a country code portion may be added as prefixes to the exchange number portion and subscriber number portion. The various portions of the remote terminal identifier are used by the local telecommunications exchange 2, and the various telecommunication exchanges forming part of the telecommunication network 4 to direct the call from the telephone device 1 to the remote telecommunication terminal 5.

The interface device 3 includes a switching circuit 6, an encoding/decoding circuit 7 and processing circuitry 8. The switching circuitry 6 is adapted to control the flow of voice or other information between the telephone device 1, the local telephone exchange 2, and the encoding/decoding circuit 7. The encoding/decoding circuit 7 is adapted to selectively receive the tone or pulse dialling signal, including the signal identifier, from the telephone device 1, and to transform the detected remote terminal identifier into a signal readable by the processing circuitry 8. The dialling signal generated by the telephone device 1 may conveniently be in the form of a DTMF signal, and consequently the encoding/decoding circuit 7 may be of the type able to recognise and convert DTMF signals. In other embodiments of the invention, the encoder/decoder may be of a type suitable to receive one or more other types of signals which may include remote terminal identifier information. The processing circuitry 8 may typically consist of a microprocessor having a central processing unit 9, a clock 10, a volatile memory 11 and a nonvolatile memory 12. The non- volatile memory 11 includes a buffer portion 11 A, a table portion 1 IB and a data storage area 11C. The table portion 1 IB is used to store telecommunications signal carrier identifier codes, each corresponding to a different telecommunications signal carrier, such as Vodafone®, Telstra®, Optus®, etc. In a position in the table corresponding to each carrier identifier code is stored variable costing information relating to one or more characteristics of the connection service provided by each carrier. The table may include, for example, entries associated with each carrier as to the price charged by the carrier to a user for completion of a telecommunication connection at various times during the day. The table may also include information as to the price charged by each carrier to establish a connection from the local telephone device 1 to a remote telephone device, which depends upon the country or other geographical zone in which the remote terminal device is located. Various other information of this type may also be stored in the table portion 1 IB.

The processing circuitry 8 is adapted to receive the terminal identifier from the encoder/decoder 7 and analyse that terminal identifier to establish which of the carriers, for which a carrier identifier is stored in the table portion 1 IB, is the most advantageous to the user of the local telephone device 1. For example, the user may intend to place a telephone call to a remote telephone device in a foreign country at a particular time of the day. In this case, the processing circuitry, having analysed the first part of the signal identifier, and having determined that it commences by an international access code part and a country code part corresponding to a particular country, will determine which carrier will provide a connection to that remote telephone device, at that time of day, to the particular country in question, for the lowest charge. The time of day information required by the processing circuitry 8 may be provided by the internal clock device 10. The processing circuitry 8 is then adapted to add a prefix representative of the selected carrier to the remote terminal identifier received from the encoder/decoder circuitry 7. The carrier prefix and remote terminal identifier are then forwarded from the processing circuitry 8 to the encoding/decoding circuit, which transforms the received information into a DTMF signal. The switching circuit 6 acting under the control of the processing circuit 8, is adapted to forward the DTMF signal, including the carrier prefix and the remote terminal identifier, to the local telephone exchange 2. The local telephone exchange 2 then forwards the call to a telecommunications device maintained by the selected carrier. The connection of the call to the remote telephone device 5 is then carried out by the selected carrier.

The functionality of the processing circuitry 8 described here within is provided, by programming code stored in the non- volatile memory 12, which causes the central processing unit 9 to perform one or more series of instructions required to achieve that functionality. The interface device 3 also includes a radio frequency receiver 13 and associated antenna 14 for receiving some or all of the information stored in the memory device 11. In this way, a remote central service is able to update pricing and other variable information from a central distribution point to a number of interface devices which may be installed at various locations. The interface device may also include porting terminals 15 and 16 enabling the connection of the processing circuitry 8 within the interface device 3 to a personal computer or other terminal 17. The personal computer 17 may be programmed to interrogate the processing circuitry 8 and receive information relating to the calls made, the time of day and the carrier selected to make each call. The processing circuitry 8 may be programmed to record this information for later recovery by the personal computer 17.

The operation of the interface device 3 will now be described with reference to Figures 2 to 11. At step 20 in Figure 2, the interface device 3 is installed between the local telephone device 1 and the local telephone exchange 2. Upon power being provided to the interface device 3 at step 21, the processing circuitry 8 is programmed to run standard diagnostic tests at step 22 to establish the correct functioning of the interface device 3. At step 23, a determination is made as to whether these diagnostic tests have been successful. If the tests are not passed, a visual indication, possibly via a flashing LED or other light source, is provided to the user of the interface device 3 at step 24. Optionally, at step 25, the processing circuit 8 may be programmed to send a remote terminal identifier identifying a service centre responsible for the maintenance of the interface unit 3, at step 25, to the DTMF encoding/decoding circuitry, which transforms the received information into a DTMF signal. The switching circuit 6, acting under control of the processing circuitry 8, is then adapted to forward the DTMF signal to the local telephone exchange 2 for forwarding to the user interface service centre. The user interface 3 may then remain inoperable until, at step 26, it is replaced.

If, however, the diagnostic tests are passed at step 23, the processing circuitry 8 determines, at step 27, whether the interface device 3 is being used for the first time, and if so, enters a "bypass mode" at step 28. In this state, the interface device 3 remains inoperable until appropriate instructions have been received from a remote central service via the RF receiver 13 enabling the functioning of the interface device 3. This bypass mode may be entered, for example, if a user of the interface device 3 has not yet correctly subscribed to an updating service, whereby the information stored in the table portion 1 IB is regularly updated. In addition, the user device 3 is enabled to receive data from the customer updating service.

If the analysis at step 27 determines that it is not the first time that the user interface 3 has been used, the time during which the device was switched off is recorded at step 29 in the memory 11 for later transmission to the central control service.

The functionality of the telephone device 1 is governed by a central task manager program. As seen in Figure 3 at step 30, the task manager causes the processing circuitry 8 to firstly determine whether the interface device 3 has been activated. If it has not, a determination is made at step 31 whether the interface device 3 is in bypass mode as described in relation to Figure 2. If the interface device 3 is in bypass mode, the task manager returns the interface device at step 32 to the ready device state shown in Figure 2.

However, if the interface device 3 is activated or in bypass mode, the processing circuitry 8 determines at step 33 whether data is being received by radio frequency from the remote central service. If such data is being received, then carrier identifiers and corresponding variable costing information is downloaded at step 34 and stored in the table portion 1 IB of the memory device 11. The task manager then causes the processing circuitry 8 to return to step 30. If incoming data is not being received, then at step 35, the processing circuitry 8 checks whether all interfaces to the interface device 3 are physically connected. If they are not, a warning device, such as a LED, is activated at step 36 and a determination then made at step 37 whether any specified interface devices are connected. Data identifying those interface devices that should be connected to the interface device 3 is stored in the memory portion 1 lC. If no interface devices are determined to be connected, the task manager returns the processing circuitry to step 30.

If one or more specified interface devices are physically connected to the interface circuit 3, the task manager then proceeds to determine at step 38 whether any incoming calls have been placed on hold and are accordingly occupying one of the lines to the local telephone exchange 2. If this is the case, a different interface device may be selected at step 39 and 40.

If the calls are on hold, or if no different interface has been requested, the task manager then makes a determination at step 41 whether any calls from the telecommunications network 4 have been or are in the process of being received by the telephone device 1. If this is the case, the task manager handles the call in accordance with the process flow shown in Figure 6. Otherwise, the processing circuitry checks at step 42 whether the telephone device 1 is on- hook, and if so returns the task manager to step 30. If the phone is not on-hook, the task manager processes the call in accordance with Figure 4. As shown in step 50 of that Figure, the task manager, having determined that no incoming calls are to be processed but that the user of the telephone device 1 has removed the handset from the handset cradle, detects whether a pre programmed emergency number is being dialled by the user. If this is the case, the processing circuitry 8 enables the generation of appropriate DTMF codes which are then switched to an appropriate destination by the switching circuitry 6. The task manager then returns the processing circuitry to step 30 in Figure 3. If an emergency number is not being dialled, the processing circuitry checks at step 52 whether the interface device 3 is in bypass mode. If this is the case, the task manager returns the processing circuitry to step 30. Similarly, if at step 52 it is determined that there are no valid interface devices connected to the interface circuitry 3, the processing circuitry is returned to step 30.

However, if no emergency number is being dialled, the interface device is not in bypass mode and there are valid interface devices connected, the task manager then checks to see whether an outgoing call is being made. If this is not the case, task manager assumes that the phone has been erroneously left off- hook at step 55, and issues an audible warning at step 56 before returning the processing circuitry to step 30. However, if dial digits are intercepted at step 57, the task manager assesses at step 58 whether a user personal identification number (PIN) is required. PIN numbers may be entered by authorised users via the telephone device 1, personal computer 17 or via the RF receiver 13, and stored in the security portion 11C of the memory device. If no PIN is required, the telephone call is processed from step 71 (Figure 5) onwards. Otherwise, the user must enter a PIN number using the keypad of the telephone device 1. If the PIN number entered is determined by the processing circuitry at step 58 to not match a corresponding authorised PIN number stored in the security portion 11C, an audible warning is generated at step 60 and the processing circuitry returned to the state defined at step 30. If a valid PIN number has been entered, however, the digits dialled on the keypad of the telephone device 1 immediately following the authorised PIN number are intercepted at step 70. At step 71, the intercepted dialled digits are compared by the task manager with phone programming digits stored in the security portion 11C of the memory device. If these intercepted dialled digits correspond to programming digits, the relevant program function is executed by the processing circuitry at step 72 and the interface device is returned to the functionality of step 30. If the intercepted dialled digits are not assessed as being phone programming digits, a check is made at step 73 whether the digits are security programming digits. If this is the case, a security programming routine, as illustrated in Figure 7 is put into operation at step 74, prior to returning the processing circuitry 8 to step 30.

The intercepted dialled digits are neither phone programming digits nor security programming digits the phone call process routine illustrated Figures 8 to 11 is put into operation at step 75.

As described previously, if an incoming call was detected at step 41, that call was handled in accordance with the process illustrated in Figure 6. At step 80, the task manager determines whether an incoming call is already in progress, and if not, receives the call at step 81. On termination of the call, the processing circuitry is returned to step 30. If it was determined at step 80 that a call was in progress, then the new incoming call detected at step 41 is signalled to the user by an audible code at step 82. At step 83, the user is able to either accept the incoming call, in which case the current call will be suspended at step 84, and the new incoming call received. Once the call is terminated, the processing circuitry is returned to step 30.

However, if the user decides to not accept the incoming call at step 83, that incoming call is cancelled at step 86 and the processing circuitry returned to step 30.

The security programming routine 74 referred to in Figure 5 is illustrated in Figure 7. According to that routine, the processing circuitry assess at step 90 whether a valid PIN number has been entered by a user, or whether the PIN number has been entered in a valid format at step 91. If either the PIN number or the format is not correct, a visual alarm will be displayed at steps 92 or 93 to the user prior to the processing circuitry being returned to step 90. At step 94, assuming that a valid and correctly formatted PIN number has been entered, the user is then able to decide at step 94 whether to purge or call characterisation information - such as the likely cost or duration of calls that that user is likely to make - from the memory device 11. If this option is selected, that purging occurs at step 95. At step 96, the user is alternatively able to purge call characterisation information associated with one or more individual users of the telephone device 1. If this option is selected, the purging of a call characterisation information for those individual or individuals occurs at step 97. If neither purging options are selected, the user is able to modify the call characterisation information stored within the memory device 11 at step 98 and then update the users identification termination code at step 99. This sequence of operations having been correctly performed, the user is provided with a visual signal at step 100.

The manner in which the interface device 3 handles the phone call process shown in step 75 will now be described. Initially, the intercepted number is scanned at step 110 for an embedded "*". If this character is found then the preceding and leading digits (up to 3) are interpreted as call characterisation information characterising the maximum cost of a call and, at step 111, stored in the buffer portion of 11 A of the memory device 11.

Similarly, the intercepted number is scanned at step 112 for an embedded "#". If this character is found then the preceding and leading digits (up to 3) are inteφreted as call characterisation information which characterises the maximum duration of the call and, at step 113 stored in the buffer portion 11A.

A determination is then made by the processing circuitry 8 at step 114 if the security feature of the interface device 3 has been activated. If active, each call initiator must suffix all calls with "**" followed by a 2 digit user identification number (UID). If the security feature is not active, any bars which may be placed on particular users of the telephone device 1 are removed at step 115. At step 116, the processing circuitry checks whether any call characterisation information, such as call or cost limitations, have been activated. If not, such call limitations are removed at step 117. The call is then processed in accordance with step 120 onwards. If it is assessed at step 114 that the user identification number security feature is active. Any detected UID limits are compared at step 118 to the cost or time parameters detected in steps 111 and 113 and if the UID user limits are exceeded, a warning produced at step 119 to the user.

If it has been determined at step 118 that the predetermined limits for that identified user will not be exceeded, the physically available device is required for placing that call checks at step 120, and any devices that are not authorised for use by that particular user deselected at step 121. At step 122, the processing circuitry 8 checks whether any limitations have been placed upon the calls that may be made by the individuals using the telephone device 1. If this is the case, the handling of the call jumps to step 127 in Figure 10. Otherwise, the processing circuitry 8 checks at step 123 whether the user identification number for the call being placed has been specified. If not, a two stroke algorithm is applied at step 124 in order to suggest the probable user identification number of the current user of the telephone. Using either the user identification number specified, or suggested by application algorithm, call characterisation information for the current user of the telephone is predicted from past use of the telephone device 1 at step 125. For example, the historical data stored in the memory portion 11C may indicate an average typical length of call for that particular user. At step 126, that typical call length is used to format a query in step 126, intended for the data table 1 IB of the memory device 11. At step 127, that table is consulted to determine an optimal communications signal carrier based upon the call characterisation information determined in step 125, or entered at steps 111 or 113. At step 128, a preferred interface device is determined. At step 129, the processing circuitry is adapted to add a prefix representative of the selected carrier to the remote terminal identifier received from the encoder/decoder circuitry 7. The carrier prefix and remote terminal identifier are then forwarded at step 130 from the processing circuitry 8 to the encoding/decoding circuit 7, which transforms the received information into a DTMF signal. The switching circuit 6, acting under the control of the processing circuitry 8, is adapted to forward the DTMF signal, including the carrier prefix and remote terminal identifier, to the local telephone exchange 2, for establishment of a connection to the remote telephone device 5 via the selected carrier at step 130.

While the call is in progress, the interface device 3 continually accumulates the elapsed time and cost of the call. Accordingly, at step 131, the processing circuitry 8 determines whether the telephone device 1 is on-hook. If this is the case, the user limits information in memory device 11 are updated at step 132 and the length of call and other call characteristics monitored at step 133.. If, however, the telephone device 1 is off -hook at step 131, the processing circuitry 38 determines whether the call remains within the predetermined security limits authorised for that user. If these limits have been exceeded, the call is terminated at step 133, and the processing circuitry return to the state defined at step 137. Otherwise, processing circuitry detects at step 134 whether the call characterisation information used to limit the call has been exceeded. If this is the case, and a termination indicator has previously been set (which indicator is detected at step 135), the call will be terminated at step 136. Otherwise, a warning signal will be generated at step 137 and the call allowed to continue prior to step 131. Finally, it is to be understood that various modifications and/or additions may be made to the interface device and method for placing a call without departing from the spirit or ambit of the present invention.

Claims

CLAIMS:

1. A method for placing a call from a local telecommunications device to a remote terminal via a selected telecommunications signal carrier, wherein the local telecommunications device is connected to a local telecommunications exchange, the method including the steps of:

(a) storing a plurality of carrier identifiers, and corresponding variable costing information for each carrier, in a memory device,

(b) detecting a remote terminal identifier emitted from said local telecommunications device,

(c) comparing the variable costing information corresponding to each stored carrier identifier with call characterisation information and selecting an optimal carrier to establish the call,

(d) adding a prefix representative of the selected carrier to the remote terminal identifier, and

(e) sending the prefix and identifier to the local telecommunications exchange for routing to the telecommunications signal carrier, so that the carrier is able to establish a connection between the local telecommunications device and the remote terminal.

2. A method for placing a call according to claim 1, wherein said call characterisation information is predicted from past use of the local telecommunications device.

3. A method for placing a call according to claim 1, wherein said call characterisation information is provided by a user of the local telecommunications device.

4. A method of placing a call according to either one of claims 2 or 3, the call characterisation information defines a likely duration of the call.

5. A method of placing a call according to either one of claims 2 or 3, wherein the call characterisation information defines a likely cost of the call.

6. A method of placing a call according to any one of the preceding claims, wherein the variable costing information relates to the charging information for establishing and/or maintaining the call.

7. A method of placing a call according to claim 6, wherein the charging information is dependant upon any one or more of the destination to which the call is placed, the time of day at which the call is placed the bandwidth of the connection, duration of the connection, or quantity of data sent during the connection.

8. A method of placing a call according to any one of the preceding claims, and further including the step of: automatically maintaining the variable costing information in said memory device from a remote central service.

9. A method of placing a call according to any one of the preceding claims, and further including the step of: maintaining the connection until a selected characteristic of the call matches the call characterisation information, whereupon said connection is terminated.

10. A method of placing a call according to any one of the preceding claims, wherein the local telecommunications device is a telephone device, facsimile device or like telecommunications receiver/transmitter.

11. A method of placing a call according to any one of claims 1 to 10, wherein the local telecommunications device is a telephone exchange to which one or more local telecommunications terminals are connected.

12. An interface device for placing a call from a local telecommunications device to a remote terminal via a selected telecommunications signal carrier, wherein the local telecommunications device is connected to a local telecommunications exchange, the interface device comprising: - memory means for storing a plurality of carrier identifiers, and corresponding variable costing information for each carrier; detecting means for detecting a remote terminal identifier emitted from said local telecommunications device; processing means for comparing the variable costing information corresponding to each stored carrier identifier with call characterisation information and selecting an optimal carrier to establish the call, and for adding a prefix representative of the selected carrier to the remote terminal identifier; and, switching means for sending the prefix and identifier to the local telecommunications exchange for routing to the telecommunications signal carrier, so that the carrier is able to establish a connection between the local telecommunications device and the remote terminal.

13. An interface device for placing a call according to claim 12, wherein said processing means acts to predict said call characterisation information from past use of the local telecommunications device.

14. An interface device for placing a call according to claim 12, wherein said call characterisation information is provided by a user of the local telecommunications device.

15. An interface device for placing a call according to either one of claims 13 or 14, the call characterisation information defines a likely duration of the call.

16. An interface device for placing a call according to either one of claims 13 or 14, wherein the call characterisation information defines a likely cost of the call.

17. An interface device for placing a call according to any one of the preceding claims, wherein the variable costing information relates to the charging information for establishing and/or maintaining the call.

18. An interface device for placing a call according to claim 17, wherein the charging information is dependant upon any one or more of the destination to which the call is placed, the time of day at which the call is placed and/or other factors, such as the bandwidth of the connection, duration of the connection, or quantity of data sent during the connection.

19. An interface device for placing a call according to any claims 12 to 18, wherein: the variable costing information is automatically maintained in said memory device from a remote central service.

20. An interface device for placing a call according to any one claims 12 to

19, wherein: the processing means acts to maintain the connection until a selected characteristic of the call matches the call characterisation information, whereupon said connection is terminated

21. An interface device for placing a call according to any one claims 12 to 20, wherein the local telecommunications device is a telephone device, facsimile device or like telecommunications receiver/transmitter.

22. An interface device for placing a call according to any one of claims 12 to 20, wherein the local telecommunications device is a telephone exchange to which one or more local telecommunications terminals are connected.